KX Riders
Maintenance & Technical => KX500 Original => Topic started by: littlewing78 on January 22, 2011, 10:02:06 AM
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I went out for a little ride today and broke my toy. I had been riding for about two hours and was on my way out of the hills. I was just coasting along and then tried to climb one last little hill. For some reason this time It took a lot of throttle to get any speed. I turned around and went back down. The problem kept getting worse and worse as I tried to get back to the road. I was able to put it in first gear and let off the clutch and the bike would just sit there like it was in neutral. At very high revs and me nearly sitting on the gas tank I was able to get it moving. When I decided to shut it down it seemed to sieze up. The kick starter wont budge. This all happened in about five minutes from when I noticed something was odd.
Any ideas what I have done? I haven't started to tear it apart yet. Just now started to drain the oil. Where should I start looking?
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oil was a good start. Anything in the oil ? like pieces of clutch plate , metal flakes. Does it smell burnt? If your lucky you broke a clutch plate and a piece of plate is lodged in the big gear on the back of the basket.This sounds like a clutch problem to me Does it have anti-freeze in it ? check the little things first.CBX
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Coolant was fine. Oil looked like normal. Milky because I need a need water seal. Didn't see any metal pieces in the oil. But when I took off the silencer a small chunk of metal fell out. Looks like possibly part of the ring (@#$%). Time to keep digging.
(http://i52.tinypic.com/2elbcef.jpg)
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Im thinking that looks a little to wide & thick to be ring . If it idled the last time you got it started I'm still thinking clutch but I've been known to be wrong.CBX
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I took of the clutch cover and rotated the basket by hand and metal chunks started coming out of the exhaust port.
(http://i53.tinypic.com/21l5rms.jpg)
So I drained the coolant and took of the head. Looks like a new piston is in order.
(http://i53.tinypic.com/2h6ew6c.jpg)
The sleeve feels smooth to the touch and I don't seen and significant gouges. Need to tear it down more now. Now I am thinking that my ring went bad and that's why I lost all power. Then me being an idiot kept running it until the ring unseated itself. Maybe.
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It just keeps getting worse.
(http://i52.tinypic.com/2pqs76h.jpg)
(http://i51.tinypic.com/ng4p6f.jpg)
(http://i52.tinypic.com/rvgaye.jpg)
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That's called a shred-o-matic.
Wow!!!
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thats awful :x :cry: :cry: :cry: :cry: :cry:
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Ok I have reached a stopping point. I need a rotor puller to get the case opened up. I think I may be able to get away with just a new piston and rings. And some new gaskets. This is my first bike and my first time ever tearing it down this much. It appears that there is no way that any of those metal pieces could have gotten into the clutch chamber. Is that correct?
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Ok I have reached a stopping point. I need a rotor puller to get the case opened up. I think I may be able to get away with just a new piston and rings. And some new gaskets. This is my first bike and my first time ever tearing it down this much. It appears that there is no way that any of those metal pieces could have gotten into the clutch chamber. Is that correct?
Correct..
But keep in mind.... main bearings and rod bearing all had pieces go through most likley...
Ooooh the joy of cast pistons.
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I know you don't want to hear it but your better off splitting the cases and replacing the main bearings and seals.
There is nothing worse than short changing yourself and then having to do it any way.
Then again, it's only time and money :cry:
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That pistom looks the same as the one i just removed from my bike. The reason for my failure was the bike over heated and melted mine the same as yours. You say you needed a new water seal maybe your bike airlocked at the head and your bike overheated just a thought as most of the damage is on the exhaust side where it is the hottest part of the piston.
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I know you don't want to hear it but your better off splitting the cases and replacing the main bearings and seals.
There is nothing worse than short changing yourself and then having to do it any way.
Then again, it's only time and money :cry:
sorry to hear of the problems
sand blaster is right. i would do nothing less the a full rebuild its just not worth cutting corners. expensive i know but in the long run its defo cheaper. the last thing you want is your expensive new parts getting destroyed by the worn out parts. new piston kit, conrod,mains and seals and recoat cylinder.
while i am here i will give my opinion as to why this has happen. from what you say in the first post it sounds like you had a clutch problem causing the motor to over rev also when rolling down hills in gear the engine can become starved of oil/petrol as you probably have the throttle closed. go karters when braking from a long fast straight pat there hand on the back of the carb to give a choking effect. this gives the motor a few quick blasts of oil and fuel. you cant do this on a bike so i normaly just pull the clutch in and give few quick revs.
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That's brutal! I agree with everyone else. I would split the cases and throw in new bearings and seals. Also check the crank journal for cracks or broken pieces. It would not surprise me if a chunk of piston lodged itself in between the case and crank. There isn't much clearance and if it did happen it could cause all kinds of issues if it's not fixed. Take lots of pics and if you have any questions there are enough of us on here to get a solid answer for you.
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Ive blown one up pretty bad before too. The piston was melted on top and there was quite abit of shrapnel everywhere too. Turned out to be lean jetting and extremely cold air temp. But man, there looks to be quite a bit of dirt residue on the crank, inside of piston and cases in your pictures. Did you knock that in there while pulling it apart or could have you been sucking in dirt to cause that catastrophe ? I think Cbmoor is mistaken, that appears to be intake side of the piston right where dirt would get sucked in first and begin the damage process. Ive seen plenty blown up by a poor intake and aged piston, that sure looks like one.
Whatever the cause may be, I agree with others, if budget allows...complete rebuild if you want it to run strong and last.
good luck
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You'd be suprised how much abuse a lower end can take. I wouldn't split the cases just yet. If it were me I get some gas and fill it up and tip the bike on its side to flush out the particles followed with some compressed air, keep repeating the process again and again till clean. Then put a small amount of 2 stroke oil on the main/rod bearings and rotate to see if everything is smooth. Grab the flywheel and try up/down movement, there shouldn't be any. If everything is in check, throw a new topend on there and ride. I know the local mechanic and others will tell you otherwise as he has to err on the safe side and puts more $$ in their pocket. I know this because we do the same at shop I work for. But I will also tell them the option above, we have had dozens of motors that have run with no issues season after season with just the flush and clean method.
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You'd be suprised how much abuse a lower end can take. I wouldn't split the cases just yet. If it were me I get some gas and fill it up and tip the bike on its side to flush out the particles followed with some compressed air, keep repeating the process again and again till clean. Then put a small amount of 2 stroke oil on the main/rod bearings and rotate to see if everything is smooth. Grab the flywheel and try up/down movement, there shouldn't be any. If everything is in check, throw a new topend on there and ride. I know the local mechanic and others will tell you otherwise as he has to err on the safe side and puts more $$ in their pocket. I know this because we do the same at shop I work for. But I will also tell them the option above, we have had dozens of motors that have run with no issues season after season with just the flush and clean method.
Would you like to see a picture of the main bearings I just took out of my motor? It had particles flow through it for exactly 30 Yards... as I coasted into camp. everything felt fine when rotating the motor by hand... But the leverage you have on everything, you will never feel a bad main untill its VERY BAD... so I tore it down, took out mains and guess what..they were crunchy... and yes the races had damage..
And as stated before... the pictures look like MAJOR DIRT INGESTION.. If as much dirt as it looks like whent through her... all bearings, crank pin's, piston, plate, etc are in order... Just my .02
"I was able to put it in first gear and let off the clutch and the bike would just sit there like it was in neutral."
This tells me you also have issues elseware... start checking clutch plates/hub..
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I agree with you Motorrad.
I have seen that exact same scenario too many times in the past as well as the consequences of trying to save a few bucks.
I wouldn't risk it based on what I saw.
Then again, what do I know....
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Then again, what do I know....
about as much as I do..
I like beer, women, and Green motorcycles.
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Don't limit yourself, I like 4 things..... :wink:
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Mottorad, I'm not saying its an absolution for everyone. There are many variables involved with how many hours were on the motor prior, oil mixture, ect before the damage took place. Every situation is different and I take that into effect whether we decide to go that route or not. Same thing as I have seem people insist on a new lower end when the topend grenades and come to find out when we pull the thing apart all the lower end components are like new.
And if your going to split the cases you better be mechanically sound or take it to someone who knows what they are doing as I have seen far too many newbies venture there and end up making things worse with they rebuild it.
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My buddies polaris snowmobile implodded twice like that before he reliezed he had torn intake boots on the bottom side and it was sucking air.I would say if you have the money rebuild the bottom end - thats the safe play, and if you were from PA I would say bring it over I can help, in less than a hour we could that out and a few beers out.CBX Oh yea have to do it while the wifes at work she seeing me rebuild motors on the island in the kitchen [zero degrees outside not gonna heat the garage just for that] :-D
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look very carefully at your cases, I've seen them blown not as bad as yours and crack the cases, a peice of piston gets in between the crank and cases and causes it to crack. as for the debate, should you split it or not, keep in mind this old saying "you can pay me now or later" and you will pay maybe even destroying your new piston.
Also, if the clutch was slipping that bad that it wouldn't go, that could have been the partial cause of your failure, a slipping clutch generates a tremendous amount of heat, coupled with a leaking water pump seal (=no coolant). yah upon reflection you more than likely caused this destruction yourself, why in the world would you not fix a failed water pump seal? water in the bearings is never a good deal.
At any rate I hope you get by with a minimal amount of failed parts.
Good luck
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I suggest you pop the cases and take a look.
I bought a KDX220 basket case that had snapped the piston skirt. With all the pieces out, the crank turned free. I was tempted to just replace the piston but resisted that urge. When I took it apart, there was a whole in the case below the crank. The crank bearings still felt like new, but I replaced them anyway after I repaired the case. Just sayin'.
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You guys all know way more than I do about this. I only got this bike 6 months ago and it is my first one. The guy I bought it from had been running it without an air filter at all. I am going to open up the case because I know there are chunks of piston inside there. I just don't have the tool to remove the magneto.
I do think most of the damage was caused by me. Just glad I got the bike as cheap as I did.
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Flywheel puller
http://www.motionpro.com/motorcycle/partno/08-0026/
Tuck\o/
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You guys all know way more than I do about this. I only got this bike 6 months ago and it is my first one. The guy I bought it from had been running it without an air filter at all. I am going to open up the case because I know there are chunks of piston inside there. I just don't have the tool to remove the magneto.
I do think most of the damage was caused by me. Just glad I got the bike as cheap as I did.
Why would you do something that stupid? It's called a "DIRT" bike for a reason.
We are all here to help however we can. I'm in mid Michigan willing to help if you're nearby.
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Thanks for all your help. I am in Utah. Time to start doing some side work so I can afford to fix this thing now.
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How much of a difference do the power valves make? Started cleaning things up and found that they were stuck closed. They had so much gunk built up on them they would not move. I did manage to get everything out and cleaned up. Now everything moves freely.
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If they were blocked off by gunk then compression should have been better. They are set up from the factory to let some compression blow by for easier starting. There is a bolt mod you can do to fix that. I'll see if I can find the post for that small mod if you like.
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Man this situation is sure turning out to be a nightmare for you. Sounds like the guy you purchased from should have no business owning a dirtbike, poor bike....
There is a plastic gear in the clutch case that actuates an arm which controls the powervalve arm. It spins a unit that moves back and fourth by centrifugal force with ball bearings and a spring. It adjusts according to the speed of the gear turning it and the engine rpms. Im wondering what is happening there while its trying to move but the powervalves are not....id look close for any kind of wear or damage and make sure there is proper operation there on that end.
That thing must have been running like a weak 250 at best, considering it's condition
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No, he shouldn't have a bike. He has a KDX right now and I am pretty sure it has been sitting outside all winter uncovered. I did see that lever that is meant to move the power valves. The thought did cross my mind that something must be going on inside if its not allowed to move when it should. Maybe since it is controlled by centrifugal force everything will be ok. No real solid connections. I will look into that when I open it up. The bike did have pretty good power but surely not what it should. I don't have much to compare it to. The only other bike I have ridden is that guys KDX and my KX blows it away. I got the bike for $750 so putting a little more into isn't breaking me yet.
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Ebay is your friend. When I completely rebuilt mine I looked all over the place for parts and found out 98% of the time ebay was the cheapest. If you do your homework you can fix everything as it were new for a decent price. I think mine ended up costing $1100 total to completely rebuild the engine. I did have to buy a new used cylinder and case halves so knock $370 off the total. Only thing that I didn't mess with was the rod/lower bearing & trans internals. All bearings, seals, gaskets, piston and rings were changed. I even got some parts from Sandblaster (OEM Cycle)
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E-bay does have some awesome deals. I just got a nearly brand new seat for $35 shipped. Rocky Mountains prices for new stuff still seem to be better.
So I played around with the motor a bit tonight. Mostly just looking for obvious damage. Aside from the piston I cant find anything else broken. I checked the water pump and it's fine. I think the seal is bad because my oil comes out milky when I change it. But wouldn't I be getting oil in my coolant? There are no sign of any at all in the water pump. I pulled the clutch plates to see if there is any obvious damage to those but I don't see anything. What should I look for with clutch plates? With it all together, I pulled the clutch lever and all seems fine. I can see the pressure plate releasing while I pull it. So no problem there. I don't have a big enough socket to remove the baskets so that's as far as I got. I am pretty certain that I need a new seal at the output shaft. When I lay the engine on that side I get oil leaking out. So Is it possible that my bike would act like it did with bad rings? I am just hoping that's the only major problem.
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often ebay has unbelievable deals on bike parts i bought a reed cage, front fender, brake caliper , hose and master cylinder all for $1 each :-o
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Measure thickness of clutch plates both friction and the metal ones. Im sure one of the Guru's here have the spec. If its stock setup they are pretty tough and long lasting, but knowing the bikes maintenence history they could be worn causing weaker performance. A good indicator of "time to replace it" wear is a little lip forming on the smooth flat surface of the metal plates and pressure plate. Check for grooves in between the basket fingers, minor ones aren't bad but deeper ones will cause clutch plates to stick (becareful not to slice your finger in there its usualy sharp ! )
Countershaft seal is easy to replace, dont forget to check the o-ring behind the collar on the shaft.
Kawasaki.com has parts diagrams you can use for parts reference while working on it. just click on owner info
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Got the case split open. Found a little surprise when I took the rotor off. There was a one inch long end of a screw driver stuck to the inside of the dish. My guess is that somebody tried to pry the rotor off and broke the screwdriver. I flushed everything out real good with oil and cleaned it up. Everything inside looks to be in good shape. I cleaned up the rest of the bike too and started putting it back together. Now I just need to start ordering some parts and bring the beast back to life.
(http://i56.tinypic.com/2ikw743.jpg)
(http://i53.tinypic.com/9r13id.jpg)
(http://i54.tinypic.com/2aez4mt.jpg)
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I got a complete Gasket set and a full set of oil seals for the bike. I think I need to have my cylinder re-plated or sleeved. I have been doing some research on both. Seems that re-plating is the best option but sleeving is cheaper. Any suggestions on those? When I put my cases back together what is the best gasket maker to use? I have a tube of high temp RTV. Will that work? Thanks
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yeah get plating. i heard sleeves slow you down because of the friction between the iron
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I recommend plating. It will last way longer and will run/cool better. IMO sleeves are junk in 2 strokes.
I prefer Hondabond to seal my cases. Never had a problem with it in 16 years that I've been rebuilding engines. It costs a little more but I would rather use the right tool for the job than have to tear down again just to re-do a sealing problem.
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Thanks goat.
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I agree with the plating.
It is more money but it has better longevity and some argue better performance.
I thought that cylinder looked a bit haggard :-o
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Plating all the way, have a reputable shop replate if you do then you can forget about it. Sleeves are old technology and require good craftsmanship when installing ( hard to find these days )
I have run many pistons thru my Maxpower plated cylinder with no honing or boring or any fuss. still looks like new, a clean tightly sealed air filter works wonders.....prob the #1 most neglected maintenance procedure in dirtbiking. Prob the #1 reason for most top end failures.
Glad u decided to rebuild, the chassis looks to be a good motivator for that.
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Plating all the way, have a reputable shop replate if you do then you can forget about it. Sleeves are old technology and require good craftsmanship when installing ( hard to find these days )
I have run many pistons thru my Maxpower plated cylinder with no honing or boring or any fuss. still looks like new, a clean tightly sealed air filter works wonders.....prob the #1 most neglected maintenance procedure in dirtbiking. Prob the #1 reason for most top end failures.
Glad u decided to rebuild, the chassis looks to be a good motivator for that.
As Greencannon stated a "Reputable" plater, I have a cylinder that was replated & has less than 4 hours run time with issues. Sent the cylinder back to the plater to offer the opportunity to "Make it Right" & with their reply I will not be using them again, & yes it was Maxpower. I have a cylinder that was plated by Rick Peterson over a decade ago & still looks great, so if the job is done right the first time you will have a product that will last a long time. I know that over time Companies can go from a first class business to a P.O.S. & the reverse can be true also, but with the $330 bad experience that I have had with Maxpower, I feel it is in the interest of KXRider members to know & have seen multiple cylinders done recently from this plater that NEVER should have left their shop! Spoke with US Chrome about their policy, and they would take care of the problem, I cant say they would or would not but another member here said they "Have" stood by their work in the past.
Okay enough stone throwing by myself, I just dont want anyone to follow my experience :-)
DoldGuy
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Hey Dold, sorry to hear about your bad experience with Maxpower. The work I had done with them was some 8+ yrs ago. I have to say the workmanship and customer service was excellent at the time. In fact my cylinder is still looking great and still in spec. Even many pistons later.
You know whats Ironic ? I first used Maxpower due to a similar bad experience with US Chrome. and I was curious about their ceramic technology
You know whats even more ironic ? Rick Petersons and MaxPower merged to form one company quite a few years ago.
Maybe the merger was a bad thing for the company....maybe you just got a "lemon" cylinder job and a "lemon" for customer service...
Maybe the companies are now buying their materials from cheaper suppliers because of economy, causing poor quality issues. We have all seen that from various industries lately.
Oh well, Im not bashing anyone here. Littlewing78, we just hope you your rebuild goes smoothly.be wise in your choices during rebuild.
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I have never had any issues with customer service at US Chrome. I have personally been dealing with them for 16 years. 3 of those years I worked for a cycle shop but I was the one talking to them and shipping everything out. I have only had 2 cylinders come back that were unsatisfactory and they took care of the issue right away. Last summer I sent my friends kx250 cylinder to them and told them to call if there needed to be anything done besides re-plating. 2 days after I shipped the cylinder they called and said they received it and stripped it. The intake bridge was cracked on top and bottom. I told them to fix it. He said everything else looked good besides the spring mount for the exhaust was worn right through. He ended up fixing that as well and didn't charge me for it. It's always been a pleasure talking with them and never thought about going to anyone else. Everyone has their preference though.
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Not sure if it has already been stated, but make sure that the folks you send it to for plating inspect the bridges between the ports. My $.02
Ben
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Ok very excited today. I just ordered a new cylinder and a new wiseco piston kit. When I get this back together what steps should I take for break in? Also I am having a hard time finding torque specs for the clutch bolts. Anybody happen to know what the torque is for a 99' KX 500? Thanks.
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if your talking about the spring bolts it should be 8 foot pounds
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Yep, the spring bolts.
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There is alot of info in this user gallery pgs. 1-30 :wink:
http://www.kxriders.com/coppermine/displayimage.php?album=259&pos=0
And Here, http://s69.photobucket.com/home/Friar-Tuck/index
:-D \o/
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Be sure to thoroughly wash your new cylinder and re-oil everything before assembly. I like to use plenty of yamalube R in my cylinder and piston, rings, powervalves, ect when assembling a top end. I like to use premix because it will burn off and not stick around and gum up like some assembly lubes.
everybody will have there preference on what they use. just be sure not to overlook that so you have a happy cylinder and top end
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IT'S ALIVE!!!!
Okay I got it all back together and its running like a champ...in 1st and 2nd gear. I got something together wrong. It wont shift higher than 2nd gear. I didn't take any of the transmission parts of gear shift parts out when I had it apart. The only thing I can think of is the clothes pin looking spring that sits just below and to the rear of the clutch basket. That fell out by accident while I had it apart. I wasn't sure of how it went back in. I am hoping that is the problem.
I bought clutch plates but didn't replace them yet. I wanted to fix one problem at a time so I could figure out what happened to start with.
There is also a little knocking going on. I am guessing that has to do with my piston / head clearance.
Very excited that is is actually running though since this is my first attempt at working on a bike.
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Yikes that looked bad! Hope that dont happen to me! :cry: Glad to hear it's running sort of... There are many sites to referance the part blow-ups for this bike, I went to service honda and printed every blow-up they had for my model and made a binder with them. Now I have the whole bike on paper. Makes it VERY easy to see WHAT goes WHERE and HOW it goes in! Just putting one small part in backwards or upsidedown can be catastrophic in an engine build. BE CAREFULL :wink: Keep us informed on how it goes.
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I was right about the spring. It popped out while I had it torn down and I put put it back in the right way but it must have popped off again while I was putting it back together. Its in the right way now and every thing is working fine.
Just has that knocking sound that worries me. Is that possibly something that will go away with break in?
This is the spring I was talking about that was in wrong.
(http://i56.tinypic.com/25tf0ci.jpg)
Here's the bike all back together.
(http://i51.tinypic.com/11wa39u.jpg)
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You hope its not the piston knocking, hopefully its just the kips
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Glad you got it up and running. Good job.
Is the stud that holds the spring apart chewed up on the end or is it just reflection? Also if the spring comes off like that again flip it over. Sometimes the work better one way than the other. I don't really understand it but it's worth a shot.
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Its just a reflection.
So any ideas on what would cause the knocking. I'm sure the piston is not hitting the head. My manual list all kinds of things it could be. Possibly timing is a bit too early? How can I check to see if its the Kips valves?
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Kips valves are quite noisy especially in a new or clean cylinder. Once it gets a nice cushion of carbon built up it will quiet down. If you followed the install directions on lining up the marks on the kips rod with the gears then there should be no issues. Did you put assembly lube on the valves when you put it together?
If it starts easy, idles and runs good then your timing should be fine. You can play with it a little and fine tune it though. Just make a mark on the stator plate and case so you know where you started from. That way if it gets worse you can go back to what it was. Just keep an eye on the spark plug. It will give you an indication on whats actually happening inside the cylinder.
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Thanks Goat. I did lube lube the valves when I put them in and I did make sure it was all lined up good. One thing I am not sure of with the Kips is the Lever that actually moves the valves. I loosened it during install. I can't seem to find any directions on where the valves should be set in relation to where the lever gets tightened back up. Does that make sense?
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I think I figured out how to set the kips. I took the cover off of the lever and started up the bike. revved it a few times and watched what it does. So it looks to me like I need to push the rod all the way in and tighten the lever in place. Sound right?