KX Riders
Maintenance & Technical => KX500 Original => Topic started by: 95formula847 on June 23, 2009, 03:20:38 PM
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Hey whats up guys this is my first post. Im now the proud owner of a 1991 KX500 that i got for $800. Its in pretty good shape for how old it is. Ive been riding my whole life but never anything this big. In the past i have had a KX125 and RM250. I currently have a ZX12R street bike.
Anyways i have a few questions about the bike. First off its pretty hard to start. And not because its physically difficult. It just doesnt want to start and idle.i have to rev it to keep it running. The bike sat for a few months so im sure it needs the carb gone through and i might as well have the jetting checked. Sound about right? Also when i get it runnin its pretty sluggish and rough in first gear and doesnt really go anywhere. If i crack the throttle and go through the gears it will eventually pick up around 4th gear but still doesnt feel near as powerful as it should. Given i ride a ZX12 on a regular basis but it still doesnt feel right. Im attributing all this with it sitting for months and needing the carb gone through? If theres a starting method you guys use that works for when i get it running right id like to know it.
Next problem it has is the front sprocket is slinging small amounts of grease. Is there a seal in there or is it somethin else? Its not slingin alot just a small amount but still... its a leak.
Third problem it has is that the rear shock is extremely soft. I weigh 200 lbs and i can just sit on it and it sinks a good bit and if i bounce ever so slightly it drops a whole bunch more. Looks like a low rider lol. Are the rear shocks rebuildable? If so is this most likely the problem... just needs a rebuild?
Last but not least the head pipe leaks where it meets the engine. When i start the bike up it puffs smoke out and has alittle oil residue. The previous owner says its been cracked in other places a few times and fixed. Its the stock pipe and has two springs holding it on. Any ideas on this? Will putting a gnarly pipe on fix the problem most likely or can the mating surface on the engine be the problem?
Oh and the front brake disc wiggles on the circular metal pieces between it and the center pice of the disc. Is this normal?
The bike is gonna be used for trail riding so id like to gear it accordingly. Ive also read a gnarly pipe is good for low end but what about a silencer to pair it with? It has a really beat up pro circuit one on it now. Im going to change the plug, drain the gas and put turbo blue race gas in it after the shop goes through the carb. Any suggestions on what plug to run? What ratio do you guys mix your fuel/oil?
Im sorry i asked alot of questions but i figured one big thread would be better than numerous small threads. Thanks alot.
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Hey whats up guys this is my first post. Im now the proud owner of a 1991 KX500 that i got for $800. Its in pretty good shape for how old it is. Ive been riding my whole life but never anything this big. In the past i have had a KX125 and RM250. I currently have a ZX12R street bike.
Anyways i have a few questions about the bike. First off its pretty hard to start. And not because its physically difficult. It just doesnt want to start and idle.i have to rev it to keep it running. The bike sat for a few months so im sure it needs the carb gone through and i might as well have the jetting checked. Sound about right? Also when i get it runnin its pretty sluggish and rough in first gear and doesnt really go anywhere. If i crack the throttle and go through the gears it will eventually pick up around 4th gear but still doesnt feel near as powerful as it should. Given i ride a ZX12 on a regular basis but it still doesnt feel right. Im attributing all this with it sitting for months and needing the carb gone through? If theres a starting method you guys use that works for when i get it running right id like to know it.
Next problem it has is the front sprocket is slinging small amounts of grease. Is there a seal in there or is it somethin else? Its not slingin alot just a small amount but still... its a leak.
Third problem it has is that the rear shock is extremely soft. I weigh 200 lbs and i can just sit on it and it sinks a good bit and if i bounce ever so slightly it drops a whole bunch more. Looks like a low rider lol. Are the rear shocks rebuildable? If so is this most likely the problem... just needs a rebuild?
Last but not least the head pipe leaks where it meets the engine. When i start the bike up it puffs smoke out and has alittle oil residue. The previous owner says its been cracked in other places a few times and fixed. Its the stock pipe and has two springs holding it on. Any ideas on this? Will putting a gnarly pipe on fix the problem most likely or can the mating surface on the engine be the problem?
Oh and the front brake disc wiggles on the circular metal pieces between it and the center pice of the disc. Is this normal?
The bike is gonna be used for trail riding so id like to gear it accordingly. Ive also read a gnarly pipe is good for low end but what about a silencer to pair it with? It has a really beat up pro circuit one on it now. Im going to change the plug, drain the gas and put turbo blue race gas in it after the shop goes through the carb. Any suggestions on what plug to run? What ratio do you guys mix your fuel/oil?
Im sorry i asked alot of questions but i figured one big thread would be better than numerous small threads. Thanks alot.
Don't know where your at but I'm using a N82M needle, 55 pilot and a 168 main. About 1 1/2 turns out on the air screw. If your idle is set to low this will also make it hard to start especially when the engine is warm.
Sounds like a bad seal and/or spacer.
Check the nitrogen precharge. Also your year bike can also use air according to the manual but nitrogen is preferred.
Mine leaks too after about 6 to 8 rides! Change crush washer, new "O" rings and use some high temp RTV to get a few extra rides out of it.
If your front brake rotor is full floating some play is normal. If you can make it click by hand front and rear and side to side it may be worn. It's a judgement call but if you don't like what your feeling when applying the brake change the rotor.
Depends on the type of oil but I think most run about 40:1.
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Welcome....for starters I run Amsoil 100:1 in all my stuff. I usually mix it at 50 to 1 and have had no problems. If you bike has been sitting a while I would start by draining the fuel tank and carburater. There is a bolt in the bottum of the float bowl to empty the carb. Start with that. Should not need any special starting proceedures. 3 or 4 kicks and you should be running.
Good luck...
Tex
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When I first got mine the guy had the idle set very low and the idle mix set very lean. Setting the carb so it will idle and adjusting the idle mix made mine much easier to start. After doing that the next time I went outside and tried to start it, it scared the crap out of me when it sprung to life on the second kick! I was used to sweating and being half worn out before getting it to start.
Also, is the plug fouled?
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The plug could very well be fouled. I havent pulled it yet. Im gonna take it today to a local shop to get the carb cleaned, jetting checked and have them do a once over. Ill decide what to fix now but i wanna start with getting it running. Then get the shock rebuilt cause the sag is rediculous.
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today i put a new plug in it. The old plug was very clean and was tan in color. I also drained the gas and put fresh turbo blue mixed 50 to 1. I rode it around and same thing. Doesnt feel much different. It still wont go more than maybe 10 mph in first before it sounds like its dieing. It fells tourquey down low but has no grunt through the middle or up top at all.
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im tryin to find out how to check the kips but cant find anything about it. is this another term for the power valve? could this be causing problems? it runs like it has the choke on. thats the best description.
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How is the pipe? is it majorly crushed or full of crap? maybe some dirt dobbers living in the tail pipe? My powervalve is sort of screwed up. It just sort of flops around. Bike still runs like a raped ape though. You can test yours though by removing the exhaust pipe and manually actuating the little control arm under the plastic cover on the side of the engine to see if it opens and closes. Can also leave that cover off with the bike running (pipe on of course) and see if revving moves the arm like it should.
Did you remove the main jet and make sure it is clean? Also see if its main jet and needle position conform atleast somewhat to http://www.kxriders.com/forums/index.php?page=11
I'm in the same boat as you though. I bought a bit of a basket case and have been going through it. I need to fix my powervalve, put in a new piston, replace several spokes, fork seals, etc... Big pain when you want to play with your new toy huh?
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The headpipe has been cracked and fixed many times, its also got a few medium dents on it and leaks at the engine flange. I took off the left grey plastic cover that has 5-6 bolts and all there was in there was a large gerey cylinder that spun? crank weight? I would really love to find a pic of what cover to take off because i have been searching for days and im completely confused at what im looking for.
I did not remove the main jet. I havnt done anything to the carb yet. Which screw is the idle screw? There is a screw with a spring and a small gold screw almost flush below that. Which is which?
And yea i want to ride so bad its not even funny. When i use to ride a few years ago on a regular basis all of my buddies thought it was boring and never wanted to get bikes/quads. Now after i have sold all my off road toys... literally 10 of my freinds got bikes and ride every weekend.
UPDATE: i took off the silencer cause it was leaking horribly where it meets the head pipe. WOW! The rivets holding the center section are all gone and its now held with one huge drywall screw. I pulled the 3 bolts out of the end of the silencer and pulled the center section out. I found the packing to be soaked with old oil and almost burnt the whole way through. It was comming apart in flakes and chunks. I rode the bike around for about a minute with no silencer and man what a difference. Bike has alot more power. So im gonna get a new silencer and a gnarly pipe. What brand silencer should i go with for trail riding to pair up with the gnarly pipe?
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95formula,
I have a FMF Gnarly that I probably will not be using if you are interested. Depending on which Coast you are closest to, I believe Motorad has one too (I am East Coast, he's West). As far as silencers, I think you would be happy with the FMF or PC
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Thanks alot pal. Ill prob be buyin brand new. If you send me pics ill def check it out and if it doesnt leak and isnt dented i might just grab it up. I live in maryland btw. Which fmf pipe should i get for trails? I have found good prices on the power core and turbine core. I like the look of the power core and the price.
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Ok guys. I got a new sprocket o-ring and collar, a clymer maintenance manual, FMF Power Core silencer and UNI multistage filter. I took the reeds out and they look new. What should they look like? Also do i take the left hand side cover off that says kawasaki on it to check the power valve? what am i looking for? when i took it off today all i saw was a large cylinder that spun. Im very mechanically inclined as im an aircraft tech i just dont try to assume with 2 stroke engines.
Also i took a look at the rear shock. There is a bottle on the right hand top side of the shock. On the bottom of this bottle it has an air fitting. Can i just try to at nitrogen at my shop and see if that helps with the crazy sag im getting? Also i took a screwdriver and pushed on the needle in the fitting and nothing came out at all. Would this mean its empty? I dont know how this system works.
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95Formula,
The cover you removed is the Stator Cover (Ignition/Generator) , the one you are looking for is on the lower right side of the cylinder (just above the water pump) it is a small plastic cover with only 2 bolts holding it in place. If you hold the Reeds up to a light, look into the Reed Cage to see if the reeds are "Lifted" off of the block itself, if so, you need new reeds. The "Bottle" on your shock is the Nitrogen Bladder Chamber, and yes it should have Nitrogen in there. If there is none, that will cause the Low Rider Effect, and for Just Testing Purposes, Put some air in the bladder (Approx 100 lbs) to see if this helps cure the effect, and if so rebuild the shock and install Nitrogen.
I am just South of the Potomac River (VA) and will send more photos if needed of the Pipe
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Might help you figure the bike out just a bit.
http://shop.thumpertalk.com/oem.asp?partcategory=381737&manufacturer=4&category=3&year=1991&model=8826
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Ok thanks alot. Ill look tonight after work for the other cover. Ill also look at the reeds and mabye post pics. And also there is nothing in the nitrogen bladder. Your not too far from me then which is good. On another note. I took the carb apart. Wasnt near as hard as i thought. i got the bowl off and found two jets. The pilot jet is a 52 while the main is a 172. Where is the needle jet number located? I know where the needle jet is but i cant seem to find a number. Also what is the gold screw for on the side of the carb below the air screw? Where should i set my air screw and this gold screw as a baseline?
95Formula,
The cover you removed is the Stator Cover (Ignition/Generator) , the one you are looking for is on the lower right side of the cylinder (just above the water pump) it is a small plastic cover with only 2 bolts holding it in place. If you hold the Reeds up to a light, look into the Reed Cage to see if the reeds are "Lifted" off of the block itself, if so, you need new reeds. The "Bottle" on your shock is the Nitrogen Bladder Chamber, and yes it should have Nitrogen in there. If there is none, that will cause the Low Rider Effect, and for Just Testing Purposes, Put some air in the bladder (Approx 100 lbs) to see if this helps cure the effect, and if so rebuild the shock and install Nitrogen.
I am just South of the Potomac River (VA) and will send more photos if needed of the Pipe
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Just looked up the jetting chart. The elevation where i live is 535 ft and its between 80-95 degress here mostly. So according to the chart i should have the N82M needle jet, the airscrew 1.5 (is this turns out from being all the way in), slowjet (pilot?) 58, needlcip in the 3rd postion ( where is the needle clip?) and a 165 main jet. I would say my jetting is way off. Mine is 52 pilot and 172 main and i havnt got the needle jet number yet.
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The jetting chart was accurate for me, for stock pipe. Jet sizes were good. When I got the pipe Pro Circuit recomends clip adjustment to one step leaner. FMF also has jetting adjustments that are specefic to the pipe, make and model. The clip adjustment is the 1-5. 1 at the top groove 5 is the bottom. 1 is the leanest setting, 5 the richest. I use a flat countertop to remove and install the little clip. If it hits carpet or shoots off, it's gone.
When you pull the powervalve cover, you should be able to grab the deal that looks like two washers stuck together and pull the actuator rod out about an inch and a half. Thats not the exact measurement, but it should be spring loaded and not hanging up. Then you can start the bike and watch it open to that full distance when you rev the motor.
The screw with the spring wrapped around it is the idle, and the brass screw is the mixture screw also called the air screw. The idle jet is also called the slow jet.
I have 97 500, same elevation. 168,58, 2nd clip position, I am puposely a little lean, in the mids. 3rd clip is probably better for typical riding. You can check your main by plug color and performance at Top-end run. Kill the motor after sustained high rpms and pull plug to see. Pilot sounds lean compared to mine.
When you pull out the slide, down in the top of it there's a 6mm nut that holds the the needle into the slide. When re-installing be sure the white plastic keeper in the spring goes all the way back down. It has a little slot and notch thing that has to line-up. Also smash the spring with finger directly to carb cap to get the most slack in throttle cable. You have to fish the end of the cable back into slot in the nut that has to be removed to get the needle out.
I watched over someone's shoulder a hundred times probably before I felt comfortable.
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Thanks alot for all the info man! I took off the plastic cover above the water pump and found what you were talking about. Theres a small arm going front to back and it is connected to a small cylinder that does in and out. It moves freely and smoothly and doesnt jam up at all. Comes out an inch or so. Not an exact measurement like you said. Thanks for helping me find it. So the powervalve isnt sticking. Nice! Now im gonna get the appropriate jets and start from there. Where can i buy sets of jets to swap in and out?
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Local Dealership will have them with no shipping costs. Otherwise its standard kehin jets from anyone that has em. I like Motosport Outlet and Midwest Action Cycles, but alot of companies carry them.
Powervalve is a go, that's good. Keep us updated on your progress.
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ok well ill start by getting the jets the chart reccomends. By then ill have the new air filter, fmf silencer, and sprocket collar/o ring on it. Hopefully it runs alittle better.
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i took it out a rode around my property. It still wont idle and is a pain to start. Im just gonna take it to a shop next week cause im gettin p.o. ed at it.
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hey doldguy you still want to sell that pipe?? :? mine has been dented badly ..R.I.P pc works pipe that some A hole spray painted black ..lol but ya im interested and in bad need of a new one.. :-P
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Sure do. :-D
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took the carb apart and found the pilot jet clogged. Put it back together and it runs way better. Rode at greenridge this weekend and weas destroyin everything in my path. Bike still wont idle but atleast it runs off idle like a raped ape. 4th gear power wheelies are no problem! its nice to be able to eat everything on the trails without even tryin. I was blowin past 450s, 250 two smokes. I rode with my bud on his raptor and he rolled it end over end tryin to stay with me. Luckily hes okay. He was a ways behind me so i didnt see him roll.
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took the carb apart and found the pilot jet clogged. Put it back together and it runs way better. Rode at greenridge this weekend and weas destroyin everything in my path. Bike still wont idle but atleast it runs off idle like a raped ape. 4th gear power wheelies are no problem! its nice to be able to eat everything on the trails without even tryin. I was blowin past 450s, 250 two smokes. I rode with my bud on his raptor and he rolled it end over end tryin to stay with me. Luckily hes okay. He was a ways behind me so i didnt see him roll.
Between your TT posts and here I'm trying to keep up. I forgot to mention in the post where I gave you jetting recommendations that this also requires a #7 slide (throat cut). So I'll post it all here. A good place to start is 55 pilot, 168 main, 1 1/4 turns out from full clockwise position (all the way in) on the air screw and a #7 slide. The needle position can be adjusted from the middle up or down as required for best throttle response off idle. The idle screw can be turned in for a high idle to get it started and then adjusted for best starting especially when warm and driveability and idle speed.
Sometimes taking a coil off the idle screw spring will help you temporarily to raise the slide a little more for a higher idle but a lot of times it's that there is wear at the contact point of the screw pin where it meets the slide.
My 500 came with a 58 pilot, 175 main and a #6 slide. I had idle, surging, starting when warm issues and was loading up quite a bit no matter how much I was on the gas. It was a little bit of a hassle but thankfully it was all tuning issues. I got a lot of help from the guys here and you'll soon figure out who some of the resident rocket scientist are. When you get the bugs worked out... all other bikes will seem like pit bikes! Good luck with your 500 and don't give up.
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ya im posting on two forums trying to get the most feedback. Im writing everything down in a notebook for reference so if anyone thinks im not listening... i can assure you i am.
Kxpegger... i will have to buy new jets tomorrow. I was planning on running the same jets you recommend. The jetting chart recommends the same for my area. How hard is it to buy the slides? Im sure it isnt cheap. My current jetting is 52 pilot and 172 main. Not sure about the slide. It doesnt have a number on it and i have yet to remove the cable from the slide cause it looks rather difficult to do. And i def wont give up on this thing. Its a blast runnin half bad. I cant wait till it runs right!