KX Riders
Maintenance & Technical => KX250 / KX125 => Topic started by: mustangfury on April 12, 2010, 04:39:18 AM
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I am having a problem with my bike bogging out in the mid range. It goes well up till about 1/4 throttle, boggs up to speed slowly from 1/4 to 3/4, then at 3/4 tears down the road like there is no tomorrow. I am also having an excess of oil that spits out the silencer when i wind it out. I think it might be the oil that isn't burning completely when the engine is bogging out. I have done one thing at a time trying for results but nothing has delivered yet. I have cleaned the air filter, checked compression, checked reed valves, and a few other things. The range of lacking performance seems to suggest it has to do with the jet needle being out of adjustment or the wrong size. I am going to try an move the clip either up or down on the jet needle but i can't seem to get the cable screw out of the throttle valve. The bike came with an fmf fatty and silencer. It also has Vforce Reed Valves. I run a 32:1 mixture which kaw. recommends using Bel Ray H1R.
My question is: how do you get the cable screw out of the throttle valve assembly? I tried to get some needle nose pliers in there but all it seems to want to do is tear up the screw.
Any suggestions on how to get it out besides drilling it or doing something that will require its replacement. Any suggestions on my general problem are welcome too.
Thanks
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mustangfury, what part on this diagram are you having difficulty with?
http://www.mxsouth.com/keihin/keihin-complete-carburetors-diagram-parts-list-of-pwk33.htm
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Finally a question that I get. The carb's upper chamber all unscrews, the little brass screw stays. You can release the clamps and turn the carb towards you a little, or pull the whole carb out. The whole top cap of the carb comes off and the slide will still be connected to the cable. The top cap should come off with your hand twisting it. Smash the spring that you will find between the slide and the cap, all the way compressed. hold the spring compressed to the lid of the carb. push the slide toward the cap for some cable slack and with a little jockeying the cable will come free of its notch.
If you look into the top of the slide, you will see a 6mm nut. That holds the needle in the slide. remove the nut and you will find the needle with a circlip stuck in one of 5 grooves. That clip is very hard to find if it shoots off there, so be careful. I lay it flat on a countertop and push the needle down while covering the clip with my hand, flip it over and snap the needle into the clip.
Moving the clip up one position will lean the mixture in mid range by lowering the needle into the hole, thereby restricting fuel flow a little bit.
When you put it back together, insert the needle and fasten with the 6mm nut, you have to again, smash the spring to the lid, then get the cable into its notch, then align the little plastic deal that keeps the cable from coming out of that notch. Make sure the throttle spring goes all the way down. Drop the slide back in there and screw the cap back on.
If this is the first time, you have been in the carb, it would be a good idea to pull it out all of the way and look it over for dirt and debris, or wear. Also good to note what jets are in it, and clip position, for future reference. I always snap the throttle a few times to make 100% sure that its working properly before starting it back up after messing with it, too.
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mustangfury, what part on this diagram are you having difficulty with?
http://www.mxsouth.com/keihin/keihin-complete-carburetors-diagram-parts-list-of-pwk33.htm
I was refering to number 14 as the cable screw and was wondering how to grip it to get it out.
Finally a question that I get. The carb's upper chamber all unscrews, the little brass screw stays. You can release the clamps and turn the carb towards you a little, or pull the whole carb out. The whole top cap of the carb comes off and the slide will still be connected to the cable. The top cap should come off with your hand twisting it. Smash the spring that you will find between the slide and the cap, all the way compressed. hold the spring compressed to the lid of the carb. push the slide toward the cap for some cable slack and with a little jockeying the cable will come free of its notch.
If you look into the top of the slide, you will see a 6mm nut. That holds the needle in the slide. remove the nut and you will find the needle with a circlip stuck in one of 5 grooves. That clip is very hard to find if it shoots off there, so be careful. I lay it flat on a countertop and push the needle down while covering the clip with my hand, flip it over and snap the needle into the clip.
Moving the clip up one position will lean the mixture in mid range by lowering the needle into the hole, thereby restricting fuel flow a little bit.
When you put it back together, insert the needle and fasten with the 6mm nut, you have to again, smash the spring to the lid, then get the cable into its notch, then align the little plastic deal that keeps the cable from coming out of that notch. Make sure the throttle spring goes all the way down. Drop the slide back in there and screw the cap back on.
If this is the first time, you have been in the carb, it would be a good idea to pull it out all of the way and look it over for dirt and debris, or wear. Also good to note what jets are in it, and clip position, for future reference. I always snap the throttle a few times to make 100% sure that its working properly before starting it back up after messing with it, too.
I've had the carb apart several times for cleanings so i'm familiar with that aspect of it. That was the first thing i did in regards to the problem. I checked the float and made sure the float needle was working properly. I have gotten as far as getting the cable out of the assembly but the cable holder screw wont break loose and i think it is just because i cannot grip it well. There is no hex nut on my carb. According to diagrams i have looked at similar to the one posted by blueoval, it is just the cable holder that screws in. I don't know if i am using a different carb than yours. it is a pwk keihin carb.
thanks for the replies
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Does this help?
You might drop some penetrating oil on it overnight. I have seen the 6mm stripped/rounded. There are a few options I can think of if it is stripped.
Needle nose vice grips.
If you have a dremmel and a small cutting burr you can carve across the the top and put a slot for a standard blade screwdriver.
If that doesn't get it a reverse drill bit might. The last resort for me would be an easy out in the hole the reverse drill bit made.
(http://i69.photobucket.com/albums/i75/Friar-Tuck/Temporary%20for%20website%20posting/DSCN1443.jpg)
(http://i69.photobucket.com/albums/i75/Friar-Tuck/Temporary%20for%20website%20posting/DSCN1455.jpg)
(http://i69.photobucket.com/albums/i75/Friar-Tuck/Temporary%20for%20website%20posting/DSCN1446.jpg)
(http://i69.photobucket.com/albums/i75/Friar-Tuck/Temporary%20for%20website%20posting/DSCN1443.jpg)
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Ahh, I thought you were working on the cable holder on top of the carb. Thats it, that is a taken off with a 6mm deep well socket on my bikes. didn't know there was different ones
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Rats...I just put those pics up a few hrs. ago.... :x
Nevermind gott 'er fixed up...
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Friar is the living schematic. Thanks, Tuck.
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Yeah the 6mm is definitely gone. It is so bad i couldn't even tell there used to be one. whoever had the bike before must have screwed it up. I was thinking about doing the dremel idea myself. I don't like cutting stuff up if i dont have to though. I tried needle nose vice grips already but it still wouldn't budge. Some of that may have to do with the fact i can't really get a good grip on it with them. it is so torn up. I will put some penetrating oil on it and try the needle nose/ vice grips one more time then the dremel idea. I'll let you know how it goes.
thanks.
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You're more than welcome & Good luck...
It may not have been that particular Piece I've fought with, but been there got the T shirt... :|
#42 if you knew how long it takes to get the simplest thing accomplished around here you'd put it on SNL..
If you Cross The Simpsons and Gilligans Island you'd be pretty close to seeing what it's like in day my Life. :-o :lol:
Tuck\o/
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Yeah the 6mm is definitely gone. It is so bad i couldn't even tell there used to be one. whoever had the bike before must have screwed it up. I was thinking about doing the dremel idea myself. I don't like cutting stuff up if i dont have to though. I tried needle nose vice grips already but it still wouldn't budge. Some of that may have to do with the fact i can't really get a good grip on it with them. it is so torn up. I will put some penetrating oil on it and try the needle nose/ vice grips one more time then the dremel idea. I'll let you know how it goes.
thanks.
I had the same problem. Dont cut it with the dremel. A flat blade screw driver will just break the cheap metal. Stay away from the needle nose vice grips too. This cost me $70. I had to buy a new throttle slide. The only other option and the one that work for me is to get a 5/16 or 8 mm six point socket on your nut driver and force it on the shoulder beneath the 6mm. It wont go on easy. You may have to tap it a few times. We use to use this method to get locking lug nuts off car wheels, when the key had been lost. I will use a photo from above to show the shoulder im talking about.
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Ther ya go PJ,
Did the same thing on the lost lug nut key and never crossed my mind to use that here... :?
Tuck\o/
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sweet. That sounds like a good idea. I did notice the vice grips wouldn't grip it too well mainly because the metal was so soft. I never got time to dremel it yet so i'm probably still good to go. I will definitely give this one a go. Just for clarification, do you actually force the socket onto the round part, kind of cutting into it along its outer edge? Is that the idea?
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Yep, You may have a better fit with an SAE socket, whatever looks close. It may require a good "rap" to get the socket to cut the cap, so be careful you don't damage the slide. That may not sound easy, however a new slide is around $60.00 and that won't come with the little cap your working on getting out right now...
Tuck\o/
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I believe the socket I used was a 5/16. It wont take much to tap it on. I used i big screwdriver and used the plastic handle end so I wouldnt mess up the throttle slide. 2 or 3 taps and will be on there.
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thanks guys! I used an 8mm socket and it went on with a few taps of the plastic screw driver handle. Worked like a charm! Great suggestion. Whoever had the bike before me had the jet needle set for the leanest setting. I put the clip on the needle back at the middle notch and the bike runs like a whole new animal! I live on a 1/4 acre piece of property but in first gear i just gave it about 1/2-3/4 throttle and it wheelied. I think that solved that problem. thanks again!
Only problem left now is that i am getting even more oil spewing out of the exhaust. I attached some pictures to give you an idea. This was oil just from the bike idling for maybe 5 minutes or so. After about 15 minutes of riding the whole back right underside of the tail will be black. Also the swing are will literally have a stream of black running down it from the oil dripping out of the joint between the fatty pipe and the silencer pipe. any ideas on this would be great.
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Silicone is your friend. Apply at every joint including the head pipe. It wouldnt hurt to tear the silencer apart and repack it as well.
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:-o
Hhhmm.. Stang, if your crank seal is ok, It looks like you may be a tad rich...
Have a look through this link:
http://www.maximausa.com/technical/oilmigration.html
If you are sure your seals are good, the next thing I would start with is what kind of riding will you be doing primarily.
Mx, recreational trail riding, dunes etc.
How hard and what level do you think you ride.
What do you have as far as mods on the bike, and do you plan on using race fuel or pump.
What is your elevation and temps.
The more info you have the better chance we have of getting you dialed in.
There is a team green jetting chart that has been really helpful for getting a starting point or baseline.
http://www.teamgreennews.ca/techside_settings.html
If you are willing to spend a little time on research and maybe a few pilot & main jets we should be able to get you real close.
Tuck\o/
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I don't know if the crank seal is ok. Supposedly it had just been replaced when I purchased the bike, but you know how that can be. What is the easiest way to check that? Is there a way i can check that without ripping the motor all apart?
I do more of trail type riding, usually sticking to the first three gears. The only other riding i do is out on my uncles farm. 40 acres of open ground so then i go wide open with it. Sometimes i like to just cruise around from point A to point B on the farm though, still pretty quick: transportation. I would say i am in the middle of mx and recreational.
I ride in elevation between 100 and 1000 feet at most and temps between 60 and 90 degrees.
i use pump fuel 93 octane.
For mods, I have an fmf silencer, fmf fatty pipe, standard bore with wiseco piston, and vforce reed valves.
I curently run 32:1 fuel:oil ratio with Bel Ray H1R.
My bike is a 1993 kx 125 J2
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You can go to 50:1, Probably should. H1R is good at lower ratios. Silencer repack is also a good suggestion. I wouldn't change much. My 250 will throw some oil on the fender, when I'm ripping on it. Clean and silicone the rubber boot that joins the silencer to the pipe. I wouldn't change jetting because of oil on my fnder and swingarm.
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Spooge, assuming a lack of mechanical problems such as leaking crank seals or bad reeds, is caused by rich jetting.
I'll come back in a bit with a longer explanation of my thoughts on that.
Thank you Stang for hanging with me. One more thing,
Do you know what you have for jetting (Main,pilot,needle and clip position presently)
Another reason the spooge factor may be so high is running from point to point on the farm, the Combustion chamber, exhaust and pipe may not have gotten hot enough to burn off the oil.
I'll be back with more after I get our 5th grader off to school.
(yes I know your thinking, are you smarter than a 5th grader?......well ... :oops: no not really!)
Tuck\o/
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IMO, Tuck the spooge is unburnt oil. Hopefully two stroke oil. At 32:1 with the High Grade H1R, would be my 1st guess as something to alter for the desired result. Since the stuff is getting everywhere, I would guess the packing is saturated. I change jetting according to performance only, spooge can happen on any bike. If you are in the tight trails or putting for awhile, then hold it WFO for any length of time, you'll have some black on the fender. Sometimes the unburnt oil in the silencer will get to smokin' like its on fire, thats what its all about. It runs good, right ?
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I meant to write down the jet needle size. I believe I remember a 2 marked on it. I have had pretty much everything apart on the bike and most of the bike settings were set at the manufacture default from the time i got it, so i believe the jet needle is probably stock for a PWK. I do not know what the throttle or main jets are but i am pretty confident in saying they are stock. I can double check all of this though. The clip position i do know is right in the middle. I do not believe this is the problem, because if i put it one step leaner, the bike goes back to the previous problem. The middle gives me the best performance.
IMO, Tuck the spooge is unburnt oil. Hopefully two stroke oil. At 32:1 with the High Grade H1R, would be my 1st guess as something to alter for the desired result. Since the stuff is getting everywhere, I would guess the packing is saturated. I change jetting according to performance only, spooge can happen on any bike. If you are in the tight trails or putting for awhile, then hold it WFO for any length of time, you'll have some black on the fender. Sometimes the unburnt oil in the silencer will get to smokin' like its on fire, thats what its all about. It runs good, right ?
That is pretty much exactly what happens. When i hit the throttle hard it really shoots stuff out and leaves a puff of blue smoke behind. The only thing is, i have repacked the silencer several times before and it just got soaked within a few minutes of riding and i was back to the same problem. I was planning on repacking it again anyway, now that i adjusted the jetting. The bike was running too lean at mid range. Would running it too lean cause extra oil out the back? I was thinking this could be it. I am sure it is loaded with oil. It just seems like it is putting out more oil than just some oil getting pulled out of the silencer. Also, would the oil be coming out of the joint in the pipe if it was just the silencer?
Finally, yes it runs great! it's just the oil problem. My only complaint is that it makes a mess. Thanks guys
also, i have a feeling it is unburnt two stroke oil. I was using a honda oil and switched to the bel ray oil, hoping the honda stuff might have been junk or something, and I noticed the consistency of what was spitting out changed so i assume that it is the unburnt 2 stroke oil. FYI:The bel ray oil definitely runs better.
BTW: That last picture i posted is the rubber cover of the governor assembly that runs into the exhaust valve. The oil is coming out of that rubber boot. I don't know if that has anything to do with the problem.
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I'll look up the stock jetting and get back with you.
If you are happy with the way the bike is running then don't change anything.
I do agree with #42 if you have a chance you might re-pack the silencer as I'm pretty sure it's soaked.
The next thing that usually follows is the packing falling apart and into and or through the pipe.
We could work through this if you like, just remember it will take time to clear out the whole system.
I wish I was smart enough to have written this all by my lonesome.."Chokey" or "Spanky" is the original author. I have attempted to take some of the "sting" out of the paper. As it is not my intent to offend anyone, least of all a poor chap actually trying to find answers, and do what's right.
Chokey's post on the subject here: 3rd post down http://twostrokemotocross.com/forum/index.php/topic,59.msg2468.html#msg2468
Spankys jetting guide:
http://www.kawasakimotorcycle.org/forum/kawasaki-motocross-offroad/17227-spankeys-jetting-guide-info-2-stroke-riders-must-have.html
Anyone that believes that spooge and plug fouling are caused by too much oil in their Pre-mix May have been misled.
If you know how to jet, you can run any amount of oil you choose, and have absolutely zero spooge.
You may not be old enough to remember, however I never saw any drooling on any factory mx bike, or for that matter any factory race bikes.
There is a prevailing myth that less oil is better. This simply isn't the case.
While true,there isn't a magic "one-size-fits-all" mix ratio, and it is possible to use too much oil for your conditions, generally speaking, more oil is better, within certain limitations.
When an engine is jetted too rich, the excess fuel leeches heat from the combustion process, causing the combustion chamber temperatures to be too low to effectively burn the oil, or even completely burn all of the fuel. The result is spooge and deposits. The spooge is nothing more than unburned fuel and oil passing out the exhaust.
It may leak from the exhaust flange at the head pipe/expansion chamber,the joint at the silencer to expansion chamber and right out the silencer tip onto your fender. The exhaust valve may be fully engulfed as well as the silencer packing.
A spooge problem, is a jetting problem. You don't get rid of the spooge by reducing the oil, you get rid of it by fixing the jetting. Correct jetting will produce an air/fuel ratio of about 14:1, which will produce combustion temperatures in the 6000F range and exhaust temperatures in the 1200F range. This will provide sufficient heat to consume the premix oil.
And,by the way is where expansion chamber producers build their pipes to operate at.
The same goes for plug fouling. Rich jetting does two things. First, it promotes incomplete combustion of the fuel and the oil due to reduced combustion temperatures. The incomplete combustion of the fuel and oil promotes deposit formation inside the engine. Second, rich jetting reduces the combustion temperatures, which in turn reduces the engines ability to burn off deposits. Combine increased deposit formation with reduced ability to burn off those deposits, and what do you get?
Spooge,plug fouling and a carbon seized exhaust valve.
Choosing a mix ratio based on the amount of oil your engine needs to provide sufficient protection and adequate ring seal.
The common misconception is that mix ratios are "one-size-fits-all", when in fact nothing could be farther from the truth.The amount of oil that is correct for one rider on his bike may not be enough oil for another rider/bike, or it may be too much oil.
It all depends on engine displacement, riding style, and how hard you push the engine.
A trail rider on a 500 that never reams the bike out (Me!)is probably fine on a mix of 50:1, where a super-fast up-and-coming future pro that screams an 85 'till the dogs howl the entire time he's on the track might not get a full day of racing out of an engine on less than 30:1.
Your engine's oil needs are determined by displacement, rev range, and the loads you put on it.
When you shut your engine down and let it sit, much of the oil drains down into the crankcase and forms a puddle in the bottom. The depth of this puddle is your indicator of whether you are running the correct amount of oil for your engine's needs. Ideally, you want this puddle to be between 1/8 and 1/4 inch. If it's less, you need more oil in your mix. If it's more, you are running more oil than you need for your conditions.
With that said, to have that amount of residual oil in the crankcase at 50:1
(a ratio made popular by magazines and oil bottles), you can't be riding very hard, or your bike is jetted richer than necessary simply to deliver enough oil.
I arrived at 40: for my bike with my riding style because that is the amount that gives me the proper amount of residual build-up, good ring seal,and a small peace of mind factor and all with out the spooge.
Small-bore engines require greater oil concentrations than larger engines to achieve the proper amount of residual build-up, because they rev higher and have higher intake velocities. Along the same lines, someone that pushes the engine harder, and keeps the revs higher, also needs to use higher oil concentrations to achieve the proper residual build-up.
To understand why the mix ratio is so important, you have to understand what happens to the oil in your fuel when it goes into the engine. While the oil is still suspended in the liquid gasoline, it can not lubricate anything.
It has to precipitate on to or into something, just like water on the outside of a cold glass in warm weather.
When the gasoline enters the engine, it evaporates, dropping the oil out of suspension.
Now that the oil is free, it can lubricate the engine.
The oil mist is distributed throughout the engine by the spinning crankshaft and the moving air currents to coat all the internal surfaces.
The oil moves through a two-stroke along with the fuel, true; but at a much slower rate than people think.
It can take 90 minutes or more for the oil migration through a two-stroke to result in a complete oil exchange on a slow trail ride, and even as much as 5 minutes for a full-throttle 20 minute moto.
The oil eventually makes it into the combustion chamber, where it is either burned, or passes out the exhaust. If the combustion chamber temps are too low, such as in an engine that is jetted too rich, the oil doesn't burn completely. Instead, some of it hardens into deposits in the combustion chamber, on the piston, and on the power valve assembly.
The rest becomes the dreaded "spooge". The key to all of this working in harmony is to jet the bike lean enough to achieve a high enough combustion chamber temperature to burn the oil, but also still be able to supply enough oil to protect the engine.
If you use enough oil, you can jet the bike at it's optimum without starving the engine of oil, and have excellent power, with minimal deposits and spooge. At 50:1 in a small-bore engine, you simply can't jet very lean without risking a seized engine due to oil starvation.
The bottom line?
Choose a mix ratio that is adequate for your needs, and jet accordingly.
You don't remedy plug fouling and spooge by adjusting your mix ratio alone,
however it does play a part in tuning your engine, to your riding style & conditions.
These are an interesting read that also supports "more oil is better" claim.
http://www.bridgestonemotorcycle.com...oilpremix6.pdf
And this is a good article as well:
http://www.maximausa.com/technical/l...summer2001.pdf
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in order to check for the amount of oil in the crank case does that mean pulling the cylinder? Also, I don't want to lean out the mixture if something else is the problem. I don't want to cause engine damage. I know i have other 2 stroke engines that i have run on more oil then they are supposed to have and they don't smoke. I agree that more oil is better to the effect of more lubrication. The point i see at which you have too much is when it kills performance or is saturated beyond reason (maybe my case). That was a good article.
When you say don't change anything, do you think i should just live with the oil problem and enjoy the performance?
Just looking at it, you can actually see the oil spitting smoke puff on my profile picture. that little puff of blue is it.
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Well, I certainly don't want to cause you any harm.
You can clean up the problem without tearing your engine down.
I have never burnt up an engine with stock jetting, or moving one jet at a time up or down. You will get into trouble dialing in a bike on a 85 deg summer day and fire up the bike and rip around on say a 40 degree day mid winter without changing anything.
I am a fair weather rider myself. I'm wracked with Arthritis and degenerative joint stuff, however I do swap things out for spring/fall and summer. Funny thing is the more you work on the bike the faster things go.
All this entails now is two pilots 50 summer 55 spring/fall. two mains 162 summer and 168 spring/ fall
I just swapped needles so I'm still experimenting and of course the air screw depends on current weather.
(I use this for warmer cooler humid dry throughout the year.)
I am afraid your silencer is soaked, I can find a thread on that if you need. Packing itself is about $15.00 or so.
Cleaning out the exhaust valve and the expansion chamber, that's gasket's and some other consumeables. If you don't need re-building wait 'till you do. Get the old girl running the way you like and then worry about that.
You certainly won't hurt anything running in your present state unless the exhaust valve gets gummed/carboned up. If you can move the assembly in and out smoothly without strongarming it your ok.
Spend a bit more time snooping around before you make a descision on where to start first or at all.
It won't cost anything and the more information you have the better decision you can make. :wink:
Tuck\o/
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How easy should the exhaust valve move in and out. i had that out about a year ago and i re oiled it and cleaned it up. there wasn't any carbon buildup that i could see at all. It looked like it didn't need it but i figured a good cleaning wouldn't hurt while i was at it. Now, opening and closing it by pulling on the governor is pretty difficult. I can do it by hand but it takes a little strength to move it. is that normal?
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If you disconnect the arm that pulls/returns the rod it shouldn't take more than a 8oz. or so of push pull to move in and out.
Think of holding a can of soup in your hand. The effort it takes to move the can up and down should be adequate to move the valve.
Here's what I found on jetting specs:
Oem 160 main FMF site 158 Main (and using Bel Ray @32:1 )
52 pilot 52 Pilot
N1AL Needle Stock needle
3rd clip 3rd clip position
11/2 turns out on the A.S. 11/2 turns out
You can be pretty safe on the FMF suggestions as they surely don't want you getting a new engine account they got your bike melted down. This should be a good place to start. you can replace the main with a 6mm socket by removing the 17mm plug on the bottom of the carb.
Cut the bottom off a water bottle to catch the fuel from the carb bowl.
Having a clean air filter and fresh fuel also helps.
Making one change at a time and keeping a log/notebook is also handy.
If you can swing a service manual or clymer specific for your bike it will make things easier for you and they also have alot of other info to boot.
Tuck\o/
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yeah i have a clymer manual i have been referencing. It has a lot of good stuff. I'll check the jets and see what size they are after i repack the silencer, and i'll go from there.
thanks all for your help. I'll let you know how things go.
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if you suspect gear oil getting sucked in past a bad crank seal you can do a simple test. with the bike running lay it to the left/ ignition side and give it some good healthy raps. note the amount of smoke and spooge. then lay the bike to the right / kicker side and give it some more healthy raps. putting the bike on the right side will put the seal in the oil and if its sucking some in you should see the difference in smoke out the exhaust. o and the gear box will need to be at the correct level before trying this. and have her up to temp. its impossible to properly evaluate jetting and such if the bike isn't completely up to temp.
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If you disconnect the arm that pulls/returns the rod it shouldn't take more than a 8oz. or so of push pull to move in and out.
Think of holding a can of soup in your hand. The effort it takes to move the can up and down should be adequate to move the valve.
Here's what I found on jetting specs:
Oem 160 main FMF site 158 Main (and using Bel Ray @32:1 )
52 pilot 52 Pilot
N1AL Needle Stock needle
3rd clip 3rd clip position
11/2 turns out on the A.S. 11/2 turns out
You can be pretty safe on the FMF suggestions as they surely don't want you getting a new engine account they got your bike melted down. This should be a good place to start. you can replace the main with a 6mm socket by removing the 17mm plug on the bottom of the carb.
Cut the bottom off a water bottle to catch the fuel from the carb bowl.
Having a clean air filter and fresh fuel also helps.
Making one change at a time and keeping a log/notebook is also handy.
If you can swing a service manual or clymer specific for your bike it will make things easier for you and they also have alot of other info to boot.
Tuck\o/
ok i checked which jet sizes were in the carb.
Main Jet - 170
pilot Jet - 52
throttle valve - #5
Jet needle clip position - 3rd
What is the difference in size? Is it the higher the richer?
Also repacked the silencer... no difference. Although the fatty pipe drained of oil so it definitely needed it. not any less than i expected.
exhaust valve assembly works like a charm. Nothing wrong at all with it. Even revved up the engine and watched the governor arm move it. No problems.
Let me know what you think. What should i start with or should i rejet at all?
Thanks
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also, my clymer manual says
Stock:
Main Jet - 168
Pilot Jet - 50 or (52 in Europe)
Throttle Valve - #5
Air Jet - 200 (could not find a number on mine?)
I'm sure this changes because of the fmf aftermarket pipe.
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Sorry for the delay Stang,
I work for the Railroad and sometimes get stuck out of town a few days.
As for the #'s on the jets yes, the larger the # the more fuel they flow.
So, from what you have right now, you are about six sizes larger than what FMF recommends with their pipe & silencer.
The FMF and Pro circuit #'s are going to be conservative, However logging your results will give you a definitive answer that your moving in the right direction and keep from doing any damage to your bike.
Actually having oil pour out of the expansion chamber should give one cause to stop and think, and certainly having the silencer soaked after a few moments of riding.
Cooler dense air will take or require more fuel. Hot thin air requires less fuel.
There is a pretty good chapter in the Clymer on the carb and jetting, look through that and see how it lines up with what we are doing as a litmus test for some peace of mind.
There is a chart in there that recommends what main,pilot and air screw position to use as determined by the altitude, temperature and humidity.
It may seem daunting now, but after the light goes on it's really not all that tough once you understand what's going on.
If you're still somewhere between 60 & 75 degrees:
Would you be willing to get the 158 main (as per the FMF spec) and a new or clean plug and take an easy ride around the farm and check the plug?
We are not looking to do a full on W.O.T. plug chop until you feel comfortable we're operating safely.
Working at one thing at a time will be easier to see the changes in running and make it quicker in the long run to get things dialed in.
Let the bike warm up to where you can just hold your hand on the cyl and take an easy 10 min or so ride around the property at say up to 3/4 throttle. let the bike cool down and check the plug.
You should notice a significant change in the way the bike reacts and the plug will start to look better.
There will still be some smoking and residual oil migrating as you found in the expansion chamber.
Not to worry, it will get better.
Keep tabs on the weather conditions and let me know how the bike runs. It will become more important the closer we get to being really close to spot on.
The first thing you should notice is the Idle will be higher right off the bat, so be prepared to either shut the bike down or be comfortable turning down the Idle when she fires up.
Tuck\o/
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ok i am going to order a bunch of jets. I found them for $2.50 a piece online plus shipping. Since the shipping is more than the jets i bought all the sizes from 158 to 168 so i don't have to go back and order another one. I just put a new plug in yesterday after repacking the silencer and it still has the same problem. I also have three more new spark plugs waiting for testing so i am set in that area. Could a float level problem be causing it to be rich or does that just effect the level of fuel in the bowl? I can check if it is at the right height, but i don't want to pull the carb again if i don't have to or if that isn't a very likely thing. I will however check it when i put in a new main jet while i'm at it.
Thanks.
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if you suspect gear oil getting sucked in past a bad crank seal you can do a simple test. with the bike running lay it to the left/ ignition side and give it some good healthy raps. note the amount of smoke and spooge. then lay the bike to the right / kicker side and give it some more healthy raps. putting the bike on the right side will put the seal in the oil and if its sucking some in you should see the difference in smoke out the exhaust. o and the gear box will need to be at the correct level before trying this. and have her up to temp. its impossible to properly evaluate jetting and such if the bike isn't completely up to temp.
did you ever try this
Could a float level problem be causing it to be rich or does that just effect the level of fuel in the bowl?
if the float r set to high or the need and seat aren't sealing fuel can flood in to the cases. but if it was that leaving the fuel on for a few minutes would flood it out right of the start and give you hell trying to start it. and if it started it would be really bad at lower RPM where you don't need all the fuel in the bowel
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yeah i tried it a couple of times and did not see any difference. I don't think it is the issue but with the amount of smoke that comes out all the time, it still could be an option. But, no, i did not see any difference tilting the bike one way or another. I'm glad you told me about this method of checking it. I had been wondering how for quite some time.
thanks for the input on the float level too.
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Hey Stang,
I think your making a good decision and yes like Big Bob says the float level will have an affect on your jetting also.
There should be a pretty good write up in your clymer on how to set your float height if you need it and the float height should also be in there usually measured in MM.'s
Should you find you don't need several of the jets you bought you should be able to sell them at what you paid for them if they are still in good shape.
If you set the float height when you put the carb together you shouldn't have to remove the carb again.
The mains are changed through the hole the 17mm nut bottom of the fuel bowl.
Get yourself something like a small chip dip tub or the bottom of a plastic bottle and cut it to fit under the float bowl so you can get your fingers to the drain plug and catch the fuel in the tub. It will keep from dumping the fuel on your case & chain or onto a rag.
Hang in there,
Tuck\o/
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i didn't think about changing them through the bottom of the bowl. that will make things a lot easier.
What size jet should i start with. i know it is best to work from richer to leaner to avoid engine damage but I also know i have a very rich jetted carb, so a change of -12 on the size might not be a bad thing. Is changing from a 170 main to a 158 main a huge difference?
I guess i'm just wondering what the overall strategy is. The strategy i had in mind was to go to 158 and see that the plug is a nice brown or if it is white i know to go up, then work our way up one jet at a time and go till we see oil then go back down one?
...process of elimination.
The only other way I thought of is elimination from high main to low main, reverse of the previous. This sticks to the start rich and work your way lean, but the only reason i wouldn't want to do that would be because i don't want the silencer getting filled with oil and giving me bad readings out the muffler as i go lower or having to repack the darn thing every time i try a lower number. Taking it easy like you suggested around the farm will prevent engine damage for that short period of time i ride while allowing me to start lean.
What fuel mixture should i run for this? 32:1? 40:1?
40:1 is currently in it. I would like to see it run 32:1 if it can though.
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Stang,
Stick with one change at a time.
Start with the FMF suggestions and we'll go from there.
The only change you will need to make is put in the 158 main. The Bel Ray Oil ratio is the same, pilot air screw etc.
You can run any mix ratio you want and still have a good running bike.
Patience Grass Hoppa.. I know how hard it is to just keep the changes slow and one at a time. This will pay off in the long run.
Take your time swapping out the main through the bottom of the carb so as not to cross or strip the threads, it really isn't so bad. You will need a small (1/4" drive) 6mm socket or jet wrench.
Here is a trick motion pro: http://www.motionpro.com/motorcycle/partno/08-0023/
Craftsman socket :http://www.craftsman.com/shc/s/p_10155_12602_00934602000P
No worries yet Matey!
Yes also on the rich to lean direction. Why take a big chance on ring, Or Worse piston seize.
I don't want you to feel like I'm yelling or you're in the principals office. Consider my suggestions and weigh them against what you have read in your clymer and what the recommended jetting specs from the pipe manufacturers are.
There really is no magic #'s as the variables are always different and changing.
Weather,elevation,wear and tear on the equipment etc. Once we get you either to a point you happy with the performance, the only changes you will have to make jetting wise to stay in the ballpark is winter summer main jet. an 8 minute process at most.
The more critical you are with performance the more changes you will have to make.
As an example a Mechanic may change jetting on the bike he's responsible for through out the day as the relative humidity,temperature and track conditions change from morning 'till evening.
Tuck\o/
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thanks i'll let you know how things go once i get the jets in and give er a test run.
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Hey Friartuck,
Do you know the stock needle part number, and what is the slock slide number - it's on the bottom of the slide near where the needle comes thru - 6, and 7 are common.
I've got an 86 kx500 and a 99 PWK air Striker - it has a #7 slide and CGH needle, 50 pilot (may be a tad lean) seems to be working fine. I plan to move to a 52 pilot and want to know what needle works best in your experience.
Also, have you done plug chops on the main jets, they seem a tad lean to me, I am running a 175 and the plug looks good, maybe a touch rich, ...
thx.
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500,
Are you asking for a 99 500 PWK ? Stock OEM is #7 slide,60pilot and a N82M 3rd clip. I have been told that a CGG is a sudco/keihin replacement #. I did not call sudco to confirm this however if you need one they can give you verification or another #.
I have a #7 slide in my 500.
98% of the guys run the stock N82M and like it. There is alot to be said about what kind of riding you do, how you ride, elevation and weather.
I have to tell you right off I am a chronic tinkerer.
The bike ran great with a 170 main 2nd clip and a 55 pilot 55-60 degrees between 3500 & 4000'
However I had to ride consistantly faster than I was comfy with, and constantly shifting to keep the bike in what I felt was a good rpm range.....Soo... I started moving things around. gearing, and then jetting.
Some things to consider 90% of our riding is singletrack, hills and skidder trails. 3500' to probably 7000'.
The fire roads we have here your lucky to get it WOT in third let alone 5th, and even the power lines are you are lucky to hit 3rd. Yes my jetting is lean by any standard.
However I am Old, Slow, and have no business riding this bike... But I love it. I can crack the throttle and pop up the front end at will and I'm about 240-245#'s. Lug it down in 1st now and I can almost idle along. Well, if I turn the Idle up a few turns I'm sure I could.
(I also have a bp7es plug in right now to see how that looks next ride, the 8 was rather wet last time out)
If someone at or near sea level on a 70deg day tried to run this set up out in the flats the wouldn't get very far before the bike gave up.
I also have 13/51 gearing and it's actually the first time I had the bike in 5th without running along the highway. I can now roll along at 10-15 mph through the trails at about 1/4 throttle. Where as prior to this I was constantly shifting 1 2nd and sometimes 3rd.
My best friend had a 99 500 and the only difference between his and my set up was he runs a 168 main and 14/48 gearing. And he rides a heck of alot harder than I do.
I hate to keep refering to my old CR but I had the darn thing dialed in great for myself. No plug fouling no spooge and the inside of the silencer was coffee ground brown.
I still am working to that on my KX and am getting close.
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Ok i got the new main jets and put the 158 in.
I am now running:
Main jet 158
Clip position 3rd
Throttle Valve #5
Pilot Jet 52
Fuel mixture 40:1
Oil Bel Ray H1R
I rode the bike around in my 1/4 acre yard for about 10 minutes and kept it between 1/4 and 1/2 throttle most of the time with 3/4 throttle for a quick dash down my sidewalk here and there. The cylinder got hot enough to where i could feel it was getting warm. It did not get super hot or anything like when i am going WOT but it just got warmed up.
At first the bike spat oil just the same but I definitely noticed a difference as the bike was warming up. At the hottest point it was still spitting a little. Once i got it up to a so so temp I shut her down and wiped up all the oil so i could start looking while it was hot. I started her up and gave her a short ride. There was not a lot on the rear fender, almost none on the swing arm, a few small drops on the rear caliper, and just a little accumulating at the back tip of the silencer. After she cooled down I pulled the plug and attached pictures show what it looked like.
(http://)
I know it was not completely hot yet but I don't go up to my uncles farm often and it is an hour and a half away. My girlfriend has a 30 acre farm though and she is only about 35 minutes away so i am hoping to go up there soon to get the bike nice and hot (like tomorrow or sometime this weekend). I don't have many places to ride where i live, so I like to take advantage of a big field to do tuning when i can. I was just wondering what would be the next step to take depending on what the plug looks like after I ride her some more, and should i rider her at full throttle and get her up to a full ride temp for a bit seeing there is still oil on the plug?
Thanks. let me know what you think. Your help has been great!
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Hey Stang,
Sounds like things are moving in the right direction. By the wet, dark oily appearance of the plug, You still probably have the oil that was previously in the crankcase working it's way through the engine. It will take some time to get the whole system cleaned out.
Here is an article worth reading through on plugs: http://www.strappe.com/plugs.html
The same guy on oil pre-mix ratio: http://www.bridgestonemotorcycle.com/documents/oilpremix6.pdf
If you can find the time to read through these two articles it would be great.
I misunderstood about the pre-mix ratio. I thought you wanted to run 32:1. that is what the FMF & Pro-Circuit bikes were running when they put out the jetting recommendations. It is up to you as to what you want to run, just stick to one ratio until we get the bike sorted out. After you are happy with the state of tune, then you will at least have a baseline to work off of. Then we can pursue any other changes you would like.
The next time you get out to the farm to do some riding, I would repeat what you did around the house and get the bike up to operating temp. Run her up to 3/4 throttle for a bit and check your plug again.
Make any pertinent notes we need to address, like "bike seems to bog at half throttle" or "doesn't pick up very clean" "throttle response in the mid range is slow" .etc.
By repeating the warm up and plug check you will verify we aren't hurting your bike and cleaning it out.
Next, =)
Is there a stretch of road or field where you can run the bike wide open 30 seconds to a minute?
What we are gonna try to do is after you got her up to temp is a plug chop. Run the bike wide open for 30 sec to a minute and kill the engine. Hit the kill switch and pull in the clutch.
What we want to accomplish is see what the bike is doing wide open. By not letting the bike Idle or decelerate using the engine compression we won't wash off the evidence on the plug.
Tuck\o/
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I do want to run 32:1 but I still had the 40:1 in the tank at the time. when i take it out to the farm i will put the 32:1 back in it.
I do have a section where i can run it wide open for 30 seconds. I will be going to my girlfriends today so I should be able to try it out.
The bike overall ran a lot better yesterday when i tested it. The throttle was a lot more responsive through every powerband. This is definitely helping.
Also, the weather conditions yesterday were 60 degrees, no precipitation, low humidity.
The forecast for today is 69 degrees, no precipitation, 30% humidity.
How should i set the idle? Should idle be set as low as possible but steady, high as possible, or in the middle? I have the air screw at 1.5 turns out like stated and that works good. I was just wondering where to set the idle screw at.
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Stang,
Your Idle is totally personal preference. You might have to mess with the air screw as the temps start to increase or decrease. Since the air screw and pilot are always open to all the circuits of your carb, this is a way to fine tune for small elevation,temp,and humidity changes. once you run out of comfortable adjustment in them it's time to make an adjustment in your main and move these back to a more conservative setting.
Ok, I got you on the 32:1 premix and finnishing up the 40:1 in the tank or fuel can.
Once your temps start to stay above 80 during the day I would change the main (for Summer) and say move to a spring spring fall change for temps of 70 to 80 and if you run winter 60 to 70 or so you might have to Change mains again.
Got to go to work . I'll be back fri night sat am.
Tuck\o/
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I know it was not completely hot yet
there is no point in puling the plug if you didn't get the bike to full temp and do a proper plug chop. the reading is worthless. get the bike to full temp then go WFO for 100 feet or more then hit the kill switch at the same back off the throttle. get your main jet set to give a good reading when WFO and then we can work on the other jetting ranges. until you get the main jetted right its almost pointless to play with the other jetting parameters.
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I took it to the farm yesterday and got her nice and hot. The bike runs a whole lot better. it has an incredible boost in power. After getting it up to full operating temperatures, I checked the plug and it seemed to be pretty much the same as when i had it around the yard but the electrode was brown and dry looking. the threads still had the same amount of oil on them. I took her wide open for about 15-20 seconds in first gear and killed it and pulled the clutch in. i looked at the plug and it looked the same as at slower speeds but maybe with a little more of a dry brown area, not much at all though. I rode her for a while with my girlfriend, about 1-2 hours, and she still developed a coating of oil on the back fender and the inside of the silencer nose was coated as well. I think it might be running just a tad bit rich still. When going about 0 to 1/4 throttle if i nailed the throttle to full it would delay a second or two before taking off. The weather was about 70 degrees with 30% humidity.
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I just replaced packing on a silencer on a ktm 105. I had just done it this time last year. The front half was totally saturated and the back half, still basically new. You want the dry brown, and the noticeable increase in power. Getting the jetting right, really helps power. You probably are just dealing with lots of oil in the packing. Its harmless, but changing out the packing will cure it, and will also help your bike, Be careful leaning it out too much. I always start a bit rich, then lean it out only to the point it runs cleanly. Silencer packing is just part of the fun. :-D
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I just repacked it before i put the new jet in. Yes it is a lot more fun and yes start rich. I was actually thinking of finding where it runs perfectly clean, then drop back one jet just to reduce wear. Thanks for the tips.
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I went ahead and ordered some more jets because the ones i originally got were all richer than the one currently in there. I'm not changing anything yet, but i want to have them on hand. Also, i figured since when in the summer, the engine needs less fuel, i will more than likely need a jet leaner than the one i currently have. I got a leaner pilot screw as well in case i need it: it was cheap. For mains i ordered: 155, 152, 150, 148; for pilot: 50.
Just letting you know what i have to work with. Thanks
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Oky Doke Stang,
You're working in the right direction! Riding around at low throttle and then whacking the throttle open you're experiencing what is called "loading up" or still just too rich.
If riding around at low throttle you just have to "Clean it out" once in a while until you get comfy with where you go with the main. I was hoping you would see a difference in the power so you wouldn't feel you were wasting your time and money. Your riding style is going to come into play the more as you get closer to what you feel is dialed in.
plonking around with a slower rider, or holding the bike at or near full throttle could be the difference of two or three main sizes. If some one else took your bike and went racing they might stay right where you are for your weather conditions.
Another guy riding single track chasing his kids may go leaner, there are so many variables its hard to just tell somebody what is gonna work for them or not sight unseen.
Please be careful from here on out. I have never had a bike seize moving one jet size. After the big jump from 170 to 158, move one at a time and keep a record of where you're at and the conditions. You can see the difference in your electrode now as far as dry and oil fouled/oily. It might take a bit more to get your exhaust cleaned out.
Hang in there!
Once you get to a place where your happy you will only have to make small adjustments
during regular maintenance between rides.
Tuck\o/
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thanks for all the help. I was planning on going down one step at a time with the main and i plan to stop when i see there are no more oil deposits on the electrode or when it just flat out performs the way i want it to. If i go till i see no more oil and the performance isn't really better than the last, i think i will go back up one size just to limit wear.
I kept cleaning up the oil that was forming on the rear fender and by the end of the day it seemed as if it was spitting more than at the beginning, so i think it started getting more added to it, plus the plug still had a little oil on the threads.
My riding style i figured would call for a leaner setting simply because i never really give it full throttle except for short runs through a field here and there. I usually run at between 1/2 and 3/4 throttle. I like doing slow maneuvering type of stuff. Drifting around turns and riding through the woods and short jumps and stuff. I rarely even get past 3rd gear most of the time.
thanks again. I'll keep you posted how things go. I really appreciate the time you've put into this for me.
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Folks took time out to help me so no worries.
I do wish I had a better ability to lay things out in easy to understand terms and or examples. However with a little research I think you got the jist of it. There really is no special secret to getting a bike dialed in. Just some patience.
Tuck\o/
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I think you did a great job of explaining things. I had the idea of how to jet it in. I just wanted some guidence from someone who had done it before. If i had just done it myself, i would have never made a big jump from a 170 main to a 158. I would have just gone one at a time and without having done something before, there is always the thought of "am i definitely doing this right?" having someone who has done it before telling you what to look for avoids that question.
thanks
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Ok, i just tried the 155 main jet and i noticed a difference with the spark plug.
Jumping to the 158 from the 170, i rode it for about 15 seconds wide open and killed the engine and pulled in the clutch. The electrode and the insulator were both a dark brown but not oily. The first three to five threads were oily though.
I put in the 155 main and rode it for about 10-15 seconds wide open and killed the engine immediately and pulled in the clutch again. The insulator was the same dark brown, but the electrode faded from dark brown near the threads to a whitish brown near the tip. The first three threads were again a little shimmery with oil.
As far as oil out the back, after riding for about an hour the rear fender was again pretty soaked with oil. It was dripping pretty good. When you nail the throttle wide open a puff of blue smoke comes out the exhaust. My guess is that maybe it is from lower end jetting being too rich. So, you're riding around at mid range and all that oil is accumulating, then you nail the gas and it coughs up a blob of that oil that accumulated. Is my logic sound?
I am more than satisfied with the top end power from both the 158 and 155 jets. The 155 was responsive all through the powerband. The 158 was a little sluggish sometimes at lower throttle ranges. I am still not satisfied with the mess that i have to clean up after i ride though. Is this a problem where i still need to go leaner than the 155,should I stay with the 155, should i go back to the 158, and is the oil spitting now just a problem with the lower range jetting?
I have pictures of the plug on my dad's phone i will try to see if i can transfer them to the computer and uploaded them asap.
Thanks
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ok here are the pics from my dads phone. These are the pics of the plug right after riding wide open for 10-15 seconds with the 155 main jet.
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These pics are the pics of the oil it is still putting out after a 1-2 hour ride. Remember i repacked the silencer before this ride.
can you add pictures to a previous post? The only way i was able to add the others was by making a new one. Sorry, for so many posts in a row.
thanks
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Stang,
Your right on about the bike "loading up" with oil while trail riding 1/4 ~ 3/4 throttle and then "Cleaning it out"
with a wide open run.
The oil & unburnt fuel collect and then get blasted out when you open her up.
I wouldn't go any leaner on your main just yet. You can clean up the bottom and midrange by raising the clip position on your needle,(lowering the needle in the seat leaning out the fuel/air ratio) and or a smaller pilot, or both.
I wouldn't go any leaner on your main just yet. Get your mid range dialed in a little closer and then have a look at the main again.
The only reason I say that is that the circuits do all overlap at some point, and the pilot circuit is always open.
So leaning out the pilot some more is gonna affect the main to some degree (although it may be a small amount)
And the same goes for the needle, The ankle bone connected to the shin bone kind of thing.
Make your next adjustment, run the bike through the gears and get it up to normal operating temp.
Adjust your air screw for the best throttle response you can get and ride!
I copied this plug chop test description from
"Spankys Jetting Guide"
" The easiest way to test it is to do a throttle-chop test. With the bike fully warmed up, find a long straight, and install a fresh plug. Start the engine, and do a full-throttle run down the straight, through all gears. As soon as the bike tops out, pull the clutch in, and kill the engine, coasting to a stop. Remove the plug, and look deep down inside the threads, at the base of the insulator. If it is white or gray, the main is too lean. If it is dark brown or black, the main is too rich. The correct color is a medium-dark mocha brown or tan. "
You still have a few other adjustments you can tinker with after you feel your bike is running as good as possible with what you have to work with now.
You can still change the throttle slide and different needle tapers. Now those are not cheap by any means, but I guess the point is there is still alot more tuning available to you should you choose to.
There should be less and less oil on your fender and the pipe joints as you continue tuning the carb and the Bikes performance should be getting noticeably better.
Keep tabs on your water and tranny fluid levels as they can also give you a fit if the seals start leaking.
You will soon be able to tell what the bike is telling you it needs by how it's running.
You are making progress Stang, Maybe not as fast as you would like , but hang in there!
Tuck\o/
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should i adjust the clip position first, then if that does not work go to the pilot/slow Jet. Before, when i had the 170 main in, i had to move the clip richer to get the bike to perform better at mid range. It was not getting enough fuel. I figured this out because the bike had better response in the mid range when i put the choke on. After making the main jet 155, i would think that moving the clip back to lean would just cause the same problem. I can still start with the clip to do a double check though, it isn't that hard.
Another question: When i store my bike, does it help make the shocks last if i put it on a stand so the wheels are off the ground? I heard this from someone and was wondering if it was true.
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Well, unfortunately either way you have to get into the carb, which ever you prefer.
Also yes on the suspension, even the weight of the bike on the springs does take some toll on them.
Even a cheapskate like me has a five gallon bucket with a small piece of wood on it to unload the suspension while not in use.
Tuck\o/
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ok so when i change the mid range jetting, to test that, do i ride around in the mid range for a while (1/2,1/4, or 3/4 throttle?) and then just hit the kill switch after it warms up to operating temp., then take a look at the plug?
I also noticed the slow/pilot jet targets more of the low speed than the mid range but has some effect on the mid range according to the diagram on keihins website.
http://www.keihin-us.com/am/_media/pdf/slide_valve.pdf (http://www.keihin-us.com/am/_media/pdf/slide_valve.pdf)
Would i test the pilot jet using the bikes idle or some midrange throttle (1/4 or 1/2)?
Here are pictures of what the plug looks like from riding around at 1/4 to 3/4 throttle with the current settings: 155 main, 3rd clip position, 52 pilot.
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Hey Stang,
Just got back from Work, The Plug chop is for the main. Yes you are right about the the circuits.
Cleaning up the midrange will prevent loading up the pipe and powervalve with excess fuel and blasting it out on your bike when you run the bike up wide open.
How is the throttle response? how is the bike running now? what is the spooge /oil factor now?
By the way,You have a great camera there, I can see the ring at the base of the porcelain in one pic and still hasn't gotten any color on it yet.
The plug looks way better than the first photo's no? The only way to verify the midrange is either with an O2 sensor or how it feels in the seat of your pants. You should be able to tell the difference of when you first started changing the jetting and now. When it was running rich & oily the sound of the engine is more of a "blubbery" sound.
The engine note should be more crisp, and your throttle response should have improved.
What you are looking to do now is get clean acceleration off Idle to wide open.
Tuck\o/
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The camera is a canon powershot sd1400. It is awesome at macro photos and photos in general. If you put it on a stand you can get the pictures even better than what i posted. I really like it. It's the nicest compact camera i've ever found.
The throttle response is great pretty much all throughout. The only time it may be a little hesitant is right at the start from a stand still. At the top end it is a beast.
At idle the muffler tip gets a little oily and begins to douse the rear fender.
The spooge/oil factor is shown in the picture of the rear fender in the previous post.
I have had finals this week at college, so I haven't had much time to mess with the bike. I will be done this monday though and my buddy and i are hoping to take a trip with our bikes sometime soon after that. I will definitely be working on it soon after monday.
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Stang, best of luck on the finals.
I was hoping the spooge was tapering off. There are needles with a larger taper, and actually with up to three different tapers. Unfortunately the needles are around $25.00 so you don't really want to buy a few and try to clean up the off Idle
without making darn sure thats what you need.
Run a few gallons of pre-mix through the bike and let me know if your still getting the plague on the fender..
Tuck\o/
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I'll definitely mess with it a bit before i get any new jets or needles. I still have a lot of options to work with.
One other thing i just thought of. If i tip my bike to one side, i can't remember which - i believe the left, by about 30 degrees or more from vertical, fuel will begin streaming out the overflow valve on the side of the carb. It will run as fast as if you had the fuel line disconnected from the carb and opened up the valve. Do you know what could be causing that? I was thinking maybe the float height? It might just be a little high but not high enough for fuel to flood into the engine unless at a slight tilt. Let me know what you think.
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That is normal. Fuel does come out when you tip it.
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So, if you lean your bike against a tree while you take a break your fuel tank may empty?
Do you just shut off the fuel to prevent that?
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ok tuck,
I did some more tests today. I put in a 50 pilot jet and ran it at all kinds of different clip positions, starting rich of course. The bike ran the best in the mid range when the clip was as rich as possible. Off the start was still bogging and mushy sounding. Off the start the bike ran the best when the clip was in the middle position. It had great acceleration then as soon as it hit mid range it nose dived forward and bogged real bad. It needed more fuel. I put the choke on then it did the opposite. Started a little slow then took off when it hit the mid range.
The plug looks a lot different. I attached pictures. The electrode is white on the intake side and black on the exhaust port. I never went WOT with it. I rode around at 1/4 to 1/2 throttle and got her nice and hot. Also, i got her warmed up to operating temp with the old plug, then switched to the new one after she was hot. The pics are of the new plug.
I disregarded the oil spitting because i know there is a lot that needs to be cleaned out that is left over from the last run. It was a lot less though. I think it may have been running a little too lean.
The bike overall performed better with the way it was before with the 52 main. the only thing that was better with the 50 was oil spitting and maybe the plug color, depending on what you think.
The weather today has been about 80 degrees and the humidity 60%. The other days tests were in 70-75 degree weather with 30% humidity.
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here are more spark plug pictures. i tried to get some to show the one side being black and the other white.
I was thinking maybe try to put the 52 pilot jet back in and then lean out the clip position. The other thing i was thinking about trying was maybe to go back to the 158 main jet and see what it does. I am going to wait till i hear what you think about everything though. If you think it is ok, i was thinking getting it up a little further in the throttle might tell us something too?
they all look lean to me but i don't know if that has to do with the fact i didn't go WOT at all. I didn't want to run it too hard since it might be lean.
thanks
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looks lean to me like melt the piston lean. its hard to imposable to get a reading on an old plug. it could look good as the extremely rich darkness is getting burn off but be way lean.
take a look at this before you ride it any more. it has a good plug chart at the bottom of the page.
http://www.bcchapel.org/pages/0003/pg11.htm (http://www.bcchapel.org/pages/0003/pg11.htm)
this is a good how to on 2t jetting
http://www.yellowdogracing.com/techstuff.htm (http://www.yellowdogracing.com/techstuff.htm)
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this is a new plug. i only rode with it for about 15 minutes.
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wite on the plug = hole in the piston.
your plug should not be wite at all.
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ok i put the 52 pilot jet back in and the color of the plug is much nicer again. It is that nice mocha brown on the electrode after riding around at 1/4 -1/2 throttle, but the plug is also very wet still. I am going to mess with the mid range clip position stuff now. I'll let you know how it goes.
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Stang,
The fuel you see when the bike is leaning over is fuel running out your overflow. The overflow is the little brass tube in the bowl of your carb, so yes, it will pour out quickly as there is no restriction on it.
The way you are describing the overflow, I would also agree your float level is too high.
The correct height will be in your manual. This could be contributing to this,
The bike ran the best in the mid range when the clip was as rich as possible. Off the start was still bogging and mushy sounding. Off the start the bike ran the best when the clip was in the middle position.
i put the 52 pilot jet back in and the color of the plug is much nicer again. It is that nice mocha brown on the electrode after riding around at 1/4 -1/2 throttle, but the plug is also very wet still.
Riding around at 1/2 to 1/4 will tend to load up the engine & plug after a while, and that may be why you found the plug to be wet again.
If the bike is running better with the choke on she needs more fuel.
Tuck\o/
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I think i may have gotten it. I got some area i could ride a little more aggressively and i did some testing. The best results were with 155 main, 52 pilot, 3rd clip position, and the air screw 3.0 turns out. I Attached pictures of the plug from the plug chop. The third picture is the best. Open the file in windows picture viewer or something and zoom in to get a good view.
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Here are the pictures of the plug after I rode around at my fairly usual style.
The bike performed wonderfully. In first or second gear if i got it at about 1/4 throttle and nailed it the bike would wheelie big time, regardless of how far forward i sat on the tank.
I also noticed the throttle slide has a slight glazed look to the bottom edges from wear. Is that a problem? I have pictures if it could be.
The oil is still spitting, but that of course is very likely just a result of the previous settings. The silencer i am sure is soaked again and the fatty pipe is probably loaded as well. You can see the threads on the plug are still a little wet in the picture, but the threads are wet all the way up in the cylinder so it could be leftovers.
Let me know what you think about all of this.
thanks tuck, i couldn't have gotten this far without your help. I think i'm almost there!
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Hey Stang,
What a difference from the first piccy's . I hope you feel this has been worth your time & money.
I think that looks great, the temps of summer will richen up your settings a tad, but that won't hurt.
I'm thinking you will be able to turn in the A.S. as temps warm up and keep you running in a "Happy Place"
Please remember that when temps start dropping in the fall you'll have to richen up.
Depending on how much time you want to spend, you could simply put in a larger main through the carb bowl.
Or go through the Whole Mary-Ann until you put the bike up for winter.
If you have been able to keep a tuning journal, a quick flip through your notebook will get you right close next time you have to tune.
Great Job!
Hopefully you have been able to inspire some other guys to get their bikes dialed in a little closer and find some extra smiles per mile!
Tuck\o/
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I actually just convinced my buddy to buy a 2000 kx125. he knows nothing about dirt bikes but has some tractor and lawnmower experience. The bike was literally just about completely disassembled. He paid $350 for it. everything is pretty much there. Just a few screws missing. I have been helping him with getting it going. it's going real well. By the looks of his exhaust pipe, it looks like he will be challenged with the same problem I just got through. I'll definitely be passing the knowledge on.
thanks again for the help,
Stang