KX Riders
Maintenance & Technical => KX500 Original => Topic started by: Lon on October 06, 2015, 01:25:49 PM
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Ok,long story short..
I just got the bike about 3 weeks ago and the big guy was a mess,17 year old kid had it for a month and about run it into the ground..
Guy told me the bike needed the rear shock rebuilt and rear caliper rebuilt,well he was soo full of it..Picked the bike up around 9pm so was dark out,bike needed ALOT more than I was told when I looked it over the next day..
Missing spacers in the rear wheel,rear shock bracket wasn't even hooked up/bolted to the frame where it gos between the frame/engine case..He needed alot of love and getting it..First pic is when I first picked it up and 2nd pic is the first day I took it out,you can see a HUGE difference after I replaced and fixed the shock..
(http://i95.photobucket.com/albums/l127/lon01_2006/Just%20got%20it%202.jpg) (http://s95.photobucket.com/user/lon01_2006/media/Just%20got%20it%202.jpg.html)
(http://i95.photobucket.com/albums/l127/lon01_2006/KX500%20all%20muddy%202.jpg) (http://s95.photobucket.com/user/lon01_2006/media/KX500%20all%20muddy%202.jpg.html)
Anyways,you can see it was in pretty ruff shape when I got it..Knowing I needed to add all the missing parts,I bought a 1993 KX500 basket case that I planned to build so I had 2 KX500's and glad I bought it because it turned into my parts bike :-( ..Guy told me it has a brand new top end and the bike does,heres how I found out..Took it for a test ride down the street after replacing parts and once warmed up,I cracked it open full throttle in 3rd gear and felt like something was choking the engine..Parked it and looked everything over real good,arm that opens/closes the power valve was missing so I grabed one off the parts bike..Before putting it on,I tried pulling the rod to open the power valve...It was stuck and wouldn't even open 1/4 ways..Blocked off the piston so I didn't spray it and hit each side of the power valves with PB-Blaster thinking its gummed up with carbon..After working it in/out for 20ish mins,its fully opening..Put the arm on and hit the trails thinking everything its all good..Well has the same issue but seems a little better,I think..So im guessing the power valve is the reason im having wide open throttle issues correct?The bike was a mess when I got it so im guessing he had the power valve apart when the top end was done,could it be installed wrong?Never had a issue like this and never had to mess with a power valve..Just feels like it choking/fueling up if I try a wide open throttle run..
Thanks in adv guys :-) ..
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BTW,
Is it true that I can pull the cover off along with the black boot then start the bike..Throttle it a few times in neutral and see if the arm/power valve rod is moving??If so,how far should the rod come out?Im guessing it comes out all the way so the power valves fully open?
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BTW,
Is it true that I can pull the cover off along with the black boot then start the bike..Throttle it a few times in neutral and see if the arm/power valve rod is moving??
yes you can...
I know you probably don't want to hear it, but you're probably gonna have to pull the jug and inspect the KIPS...for wear, broken parts, heavy carbon build-up, or hopefully just mis-aligned valves.
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BTW,
Is it true that I can pull the cover off along with the black boot then start the bike..Throttle it a few times in neutral and see if the arm/power valve rod is moving??
yes you can...
I know you probably don't want to hear it, but you're probably gonna have to pull the jug and inspect the KIPS...for wear, broken parts, heavy carbon build-up, or hopefully just mis-aligned valves.
Honestly,im glad to hear that lol..I kinda thought it was the power valve so already started thinking about buying a top end gasket set but wanted to ask and be sure first.. :-) ..I do have one other question..Is it ok to still ride it until my gaskets show up?Thanks man :-) ....
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That is tough to answer...
Could make things worse by riding it but probably not much.
Get a Cometic top end gasket kit or OEM.
If your valves were stuck chances are the top end has a lot of hours on it.
Inspect it carefully before you reassemble.
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Prevention is better than cure! (and cheaper!!!)
Pull the top end off, might be a good clean is all it needs. A few gaskets is a cheap price for the piece of mind it buys you.
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That is tough to answer...
Could make things worse by riding it but probably not much.
Get a Cometic top end gasket kit or OEM.
If your valves were stuck chances are the top end has a lot of hours on it.
Inspect it carefully before you reassemble.
Top end is brand new
(http://i95.photobucket.com/albums/l127/lon01_2006/KX500%20new%20piston%201.jpg) (http://s95.photobucket.com/user/lon01_2006/media/KX500%20new%20piston%201.jpg.html)
(http://i95.photobucket.com/albums/l127/lon01_2006/KX500%20new%20piston%202.jpg) (http://s95.photobucket.com/user/lon01_2006/media/KX500%20new%20piston%202.jpg.html)
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BTW,
I am pulling the jug and checking the power valves for sure,just ordered the top end gasket set..Im about to take the cover/boot off the power valve then start the bike and see if its moving and how far its moving...I'll also take some videos and post them,that way you guys can see whats going on...Thanks for the replys guys :-) ..
Not sure why but this site is moving turtle slow for some reason...
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Is it ok to still ride it until my gaskets show up?Thanks man :-) ....
I myself wouldn't ride it until it's squared away....remember, you/we don't even know what the problem is yet.
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Remember, a new piston is not a new top end... It's just a new piston, rings, and bearing...
That is normal maintenance.
Having trouble with your exhaust valves right after a new piston is installed is telling us that there is something not quite right.
When you get the top off, check for cracks around the intake and exhaust bridges...
Look for any discoloration of the plating... Discoloration is often a sign that the plating is done or close to being done.
Remove your exhaust valves and look for broken or chipped teeth.
Remember, that exhaust valve assembly should move as smooth as butter if it's working right.
Something else to check for while you have it apart is your reed pedals.
Make sure they sit flat with no gaps and make sure they are not cracked or frayed around the edges.
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I don't know how to post a video on here yet but heres the link --------> https://www.youtube.com/watch?v=EirlCkrFbZw
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not the most crystal clear vid, but they do "appear" to be opening/closing fully.
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not the most crystal clear vid, but they do "appear" to be opening/closing fully.
I tried but its super hard trying to hold the phone,flash light and move the power valve rod at the same time lol...Well heres the running video and looks like everything is working like it should but not 100% sure as I never saw one moving while running lol..
Next step is to put everything back together the pull the carb/reed cage and check reeds..Then i'll pull the carb bowl off and check jets...What it feels like is its loading up pretty good past 1/2 throttle and you can hear it in the video,well I hope you can..
Heres the running video----> https://www.youtube.com/watch?v=rNtzX-MUjho ..
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What it feels like is its loading up pretty good past 1/2 throttle and you can hear it in the video,well I hope you can..
Heres the running video----> https://www.youtube.com/watch?v=rNtzX-MUjho ..
funny...one of the 1st things I noticed in your 1st vid, was how much black spooge was around the exhaust outlet/cylinder, like it was running extremely rich.
Definitely pull the carb and find out exactly what your current jetting is...Main, Pilot,
look at the needle closely, and post the numbers and letters that're stamped into it, so we know which needle is in there, and what position the needle clip is in too.
it also "looked" like your governor rod seal was leaking too...the rod you were pulling in and out in the 1st vid.
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+1. I had similar symptoms mine was a bad coil. Get your carb cleaned up check your jetting and start testing electronics. I believe it was sandblaster who did a write up about testing and specs that's what got me pointed in the right direction
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This is Sandblaster's electronics trouble shooting guide that I used when mine wouldn't start. It's really helpful if you are a little rusty (or confused) on electronics. I actually printed it out and put in a coil bind with my KX manual I found online.
http://www.oem-cycle.com/forum/viewtopic.php?f=40&t=163 (http://www.oem-cycle.com/forum/viewtopic.php?f=40&t=163)
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Well didn't get far,still gotta take the bowl off and check the jets ..Did check the reeds and the bottom half had a pretty good gap so flipped both top and bottom reeds,no gap but still getting a new set..Pulled the plug and its for sure running rich as hell and I think its from the reeds..I could almost slide a dime in the reeds,thats how big the gap was..Still plan on checking the jets and will post numbers tomorrow..
(http://i95.photobucket.com/albums/l127/lon01_2006/Picture%20002_4.jpg) (http://s95.photobucket.com/user/lon01_2006/media/Picture%20002_4.jpg.html)
(http://i95.photobucket.com/albums/l127/lon01_2006/Picture%20001_5.jpg) (http://s95.photobucket.com/user/lon01_2006/media/Picture%20001_5.jpg.html)
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Ok,got the carb apart ..Bike is stock other than pipe,FmF Gold Series ..
Slow jet --> 60
Main jet --> 168
I also pulled the bowl off the carb that came with my parts bike and these are the jets it has..
Slow jet --> 48
Main jet --> 158
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what's your elevation?...ballpark guess.
keep the 168 main jet in there for now....
but get a 55 pilot/slow jet...
what position is the clip in, on the needle?....and try to read the digits stamped on the needle.
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what's your elevation?...ballpark guess.
keep the 168 main jet in there for now....
but get a 55 pilot/slow jet...
what position is the clip in, on the needle?....and try to read the digits stamped on the needle.
Looked up sea level and were around 575 above..
I'll get the 55 jet but could I use the 48 jet from the other carb for now?
C-Clip is in the very top/first slot of the needle and numbers on it are N82M..I also checked the needle from the parts bike carb and it has N85C on it..
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could I use the 48 jet from the other carb for now?
C-Clip is in the very top/first slot of the needle and numbers on it are N82M..I also checked the needle from the parts bike carb and it has N85C on it..
I'm starting to wonder if you don't have a bad clutch side crank seal....your plug should be white as hell, and running dangerously lean with those settings!
have you noticed your tranny oil mysteriously going low?....does it smoke excessively?
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could I use the 48 jet from the other carb for now?
C-Clip is in the very top/first slot of the needle and numbers on it are N82M..I also checked the needle from the parts bike carb and it has N85C on it..
I'm starting to wonder if you don't have a bad clutch side crank seal....your plug should be white as hell, and running dangerously lean with those settings!
have you noticed your tranny oil mysteriously going low?....does it smoke excessively?
Nope,not using a drop of oil (ATF Type-F) from the crank case..Just the normal 2 stroke smoke and if the seal was bad,it would be smoking white pretty good...Can't smell it either and ATF smells nasty as hell..
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don't use that 48 Pilot...that's too big of a jump at once...drop the needle clip into the 2nd from top.
something's not adding up...your settings are way leaner than mine...and I run within a couple hundred feet of your elevation, and I'm running very lean.
I think a leak down test should be the next thing on your menu...something's wrong.
*EDIT*
what 2 stroke oil are you using?, and what ratio are you mixing it at?
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don't use that 48 Pilot...that's too big of a jump at once...drop the needle clip into the 2nd from top.
something's not adding up...your settings are way leaner than mine...and I run within a couple hundred feet of your elevation, and I'm running very lean.
I think a leak down test should be the next thing on your menu...something's wrong.
*EDIT*
what 2 stroke oil are you using?, and what ratio are you mixing it at?
Go easy on me,im still learning all this :-) ..
Could the reeds give the top end power issue im having or no?When I checked them,the whole top half had a nice size gap..Was big enough that I could slide a penny or dime between the reeds and cage.I already flipped them and all are nice and flat now but haven't started it yet..
I'll get the 55 jet asap but I have a question about it also..Could that give the top end power issue,running too lean?
I clearly have alot to lean and I couldn't thank you enough so far for the help man..Been wanting a KX500 for a good 20 years as its my dream bike..Now that I have it,I wanna do everything the right way down to a "T" ..
I'll also do a leak down test in the next few days just to be 100% sure..
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Oops,missed the edited..
Running Klotz mixing it 32:1 ..
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yeah, replace the reeds a.s.a.p. if they were that bad....no sense playing with jetting if they are that gapped and worn.
how did you check that spark plug?...to do it correctly, you want to run it on a straight-away wide open for a couple seconds, providing you have a place that allows you to go that fast. Then pull in the clutch and hit the kill switch immediately whilst you're still coasting...then pull the plug and check it's color. This will tell you what you need to do...whether to go richer or leaner.
I would keep the riding to a minimum until the issue gets figured out....or it could turn very expensive very quickly.
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mixing it 32:1 ..
that's not bad...
a few of us are running 40:1
I've never used Klotz...just Bel-Ray and Motul
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Well Foxx,you were on the money bro..My dang crank seal is done :-( ..I didn't wanna believe it because the bike was running like a top but I could feel top end power was a dog..Thinking it was the reeds when I saw how bad they were so flipped them and waited until we went riding..Well we went yesterday and the first 45mins to a hour were good..Low end was ALOT better but top end was the same,got worse as the crank case oil/ATF was fouling the crap out of the plug to the point where it was breaking up pretty good..Just putted it around with my son but kept a eye on the oil level which did drop some..I always run the oil level a little below the top of the site hole..Kept a eye on it and by the end of the day,it dropped down to the middle of the site hole..
This wasn't a big deal until I found out I gotta split the d**n cases JUST to change the d**n seal which is pretty stupid..Turns a 1 1/2 to 2 hr job into a few day job over a stupid seal but its all good..Bike is new to me so now I get to go through and check everything while its apart ...
I already have YamaBond for the cases when I put them back together so ordering the Tusk oil seal kit so I can replace them all..
What a pain in the ass over one seal :-P ..
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Well Foxx,you were on the money bro..My dang crank seal is done
I know.
your jetting and plug color gave it away.
someone was trying to jet it as lean as they could to bypass the bad crank seal...whether the previous owner knew he had a bad seal or not, I don't know...probably not.
Either way...at this point, replace as many bearings and seals that your wallet/wife will allow you to spend, since you have to split the motor open anyways....definitely replace BOTH crank bearings and seals regardless!!...go over the tranny really good too.
Be sure you have a service manual for easy reference ...you can find them cheap all day long on e-bay...don't be afraid to ask questions...a lot of info is already in this site, you just have to use the "search" option.
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Well Foxx,you were on the money bro..My dang crank seal is done
I know.
your jetting and plug color gave it away.
someone was trying to jet it as lean as they could to bypass the bad crank seal...whether the previous owner knew he had a bad seal or not, I don't know...probably not.
Either way...at this point, replace as many bearings and seals that your wallet/wife will allow you to spend, since you have to split the motor open anyways....definitely replace BOTH crank bearings and seals regardless!!...go over the tranny really good too.
Be sure you have a service manual for easy reference ...you can find them cheap all day long on e-bay...don't be afraid to ask questions...a lot of info is already in this site, you just have to use the "search" option.
To be honest man,the guy I got it from knew d**n good and well he f**ked me big time....Before we traded,he told me the bike only needed the rear shock rebuilt and rear caliper rebuilt..Also he wouldn't meet me during the day so I can see the bike really good,claimed he worked alot of hrs and all kinds or other BS storys..But being me and wanting my dream bike (sounds stupid but it is lol) for a good 20 years,I fell for his BS..But it is what it is and im doing what I can to get everything done right which I have so far..Main reason I bought a 1993 KX500 basket case,so I can fix this one..
When I split the cases,i'll check everything over for sure..Just really sucks people can't be upfront and honest anymore...Thanks man...
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Believe me you will be happier and feel a lot better once you go through the whole thing!! Very rare that you will find one that doesn't need much unless you are paying top dollar and even then you may as well go through it top to bottom. Don't let it get ya down, you will be very happy. I know it my K5 and my T4 were my dreams finally almost ready to tackle my T4 that's been neglected for the last 2 years
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I didn't know you had a t4
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Believe me you will be happier and feel a lot better once you go through the whole thing!! Very rare that you will find one that doesn't need much unless you are paying top dollar and even then you may as well go through it top to bottom. Don't let it get ya down, you will be very happy. I know it my K5 and my T4 were my dreams finally almost ready to tackle my T4 that's been neglected for the last 2 years
Please take lots of pictures. I regret selling my 88 T4 every time I see one on Craigslist. That dude was stupid fast.
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I didn't know you had a t4
Yea got it a year after the K5, she is well worn but runs pretty well. 1988 with white plastics. I will bring it out to Corral if you make it this weekend
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Believe me you will be happier and feel a lot better once you go through the whole thing!! Very rare that you will find one that doesn't need much unless you are paying top dollar and even then you may as well go through it top to bottom. Don't let it get ya down, you will be very happy. I know it my K5 and my T4 were my dreams finally almost ready to tackle my T4 that's been neglected for the last 2 years
Please take lots of pictures. I regret selling my 88 T4 every time I see one on Craigslist. That dude was stupid fast.
I will try still can't get pics on here no matter what I try. I hate technology!!!! :lol: