Bottom end/Transmission issues

[Danger4u2]

Post your questions/answers here.

[mustangfury]

This question is for a 125.

When the engine on my bike is running, there is a tapping noise that comes from the crank area.  It could be from the clutch or the transmission.  I am not sure what it is.  It does it when the bike is in neutral and in gear. The tapping increases with engine speed.  It is a very light sounding tap but it is still there.  Sometimes it is louder than others.  The best way i could describe it would be to take and run the plastic handle of your toothbrush across the rollers on your chain fairly quickly.  The noise is not coming from the cylinder. I don't know if this is normal transmission noise or if there is a problem.

There is no slipping in the clutch. I had the clutch apart about a year ago and everything in there looked like it was just out of the shop.  The gears do not grind when shifting and the bike shifts very smoothly. there is no performance issues, i just want to be proactive on a possible future problem.  I don't know if some bearing is wearing out or something.

Any ideas?

thanks,
Stang

[cutting torch]

Does your kick idler gear still have a bushing in it? The '87 I got had lost it's bushing and the snap ring that retained it to the end of the output shaft. It did a bang-up job on the back of the clutch basket!

That's all I can think of that would make a very noticable racket. 

torch

[junk man]

hey guys i have a question
will a kx250 kick starter fit on a 97 500 engine are the shafts the same size 
also the engine is in a 2000 kx250 frame

thanks for any help   JM


hey torch thanks

[cutting torch]

No, different shaft size.

torch

[Hillclimb#42]

This question is for a 125.

When the engine on my bike is running, there is a tapping noise that comes from the crank area.  It could be from the clutch or the transmission.  I am not sure what it is.  It does it when the bike is in neutral and in gear. The tapping increases with engine speed.  It is a very light sounding tap but it is still there.  Sometimes it is louder than others.  The best way i could describe it would be to take and run the plastic handle of your toothbrush across the rollers on your chain fairly quickly.  The noise is not coming from the cylinder. I don't know if this is normal transmission noise or if there is a problem.

There is no slipping in the clutch. I had the clutch apart about a year ago and everything in there looked like it was just out of the shop.  The gears do not grind when shifting and the bike shifts very smoothly. there is no performance issues, i just want to be proactive on a possible future problem.  I don't know if some bearing is wearing out or something.

\

I had a ktm 105 making a noise like that. I was afraid I had a piston skirt noise or crank bearing problem. Turned out to be the factory rivots that held the big gear to the clutch basket. It was the loudest at a low idle.

[mustangfury]

Does your kick idler gear still have a bushing in it? The '87 I got had lost it's bushing and the snap ring that retained it to the end of the output shaft. It did a bang-up job on the back of the clutch basket!

That's all I can think of that would make a very noticable racket. 

torch

How do i check to see if the bushing is still in there?  What does it look like? Can you show me what it is with a parts diagram or picture?

I had a ktm 105 making a noise like that. I was afraid I had a piston skirt noise or crank bearing problem. Turned out to be the factory rivots that held the big gear to the clutch basket. It was the loudest at a low idle.

Was this a problem that you fixed or needed to fix, and if so, how do i check for it and fix it?


Thanks guys. I appreciate it.

[Hillclimb#42]

Either way, you will have to pull the cover. It almost always tears the gasket, if you don't have an extra to throw on there. There is a white plastic collar that you should be able to see wrapped around the kick shaft. The rivots that I refer to are on the backside of the clutch basket. They hold the gear to the basket, which would pulling the whole basket. I would tyr to see if there is any play in it front to back rotation and in and out from the center case. I mean to say check for slop in the clutch basket. I'm not 100% sure you would be able to see the slack that makes a noise or not. I installed a hinson basket and new cushoins and the noise was gone. It took a long time to track it down. A owners manual is a must, if you are going to tear it down.

[mustangfury]

I have a clymer manual on the bike, so i should be good as long as it does not require special tools or a press.

I had the cover off previously without tearing the gasket so I'll try to be careful.

What are the rivots rubbing against to make the noise? 

[greencannon]

Every KX bike I've had from 80cc to 500 has made "that noise"  for the life of the bike.
 Kawasaki 2 stroke motors sound like nuts and  bolts jumbling inside when running perfectly normal. I'm sure some other KX or KDX owners can agree on that.
If there isn't any (out of spec) play in any of the major components and no performance issues, then run it hard...

[mustangfury]

Either way, you will have to pull the cover. It almost always tears the gasket, if you don't have an extra to throw on there. There is a white plastic collar that you should be able to see wrapped around the kick shaft. The rivots that I refer to are on the backside of the clutch basket. They hold the gear to the basket, which would pulling the whole basket. I would tyr to see if there is any play in it front to back rotation and in and out from the center case. I mean to say check for slop in the clutch basket. I'm not 100% sure you would be able to see the slack that makes a noise or not. I installed a hinson basket and new cushoins and the noise was gone. It took a long time to track it down. A owners manual is a must, if you are going to tear it down.

I was able to look through the oil plug at the kick start gear and i could see the white bushing was still in tact.  I was also able to put the bike in gear and turn the back tire to feel for the tap.  I don't believe it is coming from the clutch or the right side of the motor.  I think it is coming from the left side.  That is where i could feel the tap while the engine was running.  I could feel it through the flywheel cover.

Every KX bike I've had from 80cc to 500 has made "that noise"  for the life of the bike.
 Kawasaki 2 stroke motors sound like nuts and  bolts jumbling inside when running perfectly normal. I'm sure some other KX or KDX owners can agree on that.
If there isn't any (out of spec) play in any of the major components and no performance issues, then run it hard...

This sounds fair.  I assumed it could be the case, but just to be on the safe side, can anyone else confirm this?  With no performance issues, i was tempted to leave it alone.
thanks.

[mustangfury]

I was able to turn the transmission drive gear in neutral to hear the tap.  I checked under the stator cover and made sure it wasn't coming from there.  I think you may be right about the clutch basket rubbing hillclimb.  It makes the noise if the clutch has just a slight drag.  It does it if you put a little pressure on the shift lever to just about enable the bike into 1st gear but yet keep it in neutral. If you get the bike completely in the middle of neutral the noise goes away.  Will the basket rubbing as soft as it is cause damage or just noise?  IOW did your ktm have any damage from it?

Another question,  when you take out the spacer behind the drive sprocket, if oil is coming out, does that mean the seal is bad.  Something in there is leaking oil onto the chain and my guess is the seal, but i was wondering if oil would come out without the spacer in there even if the seal was good.

Thanks

[Hillclimb#42]

The rivots did not rub anything. They just gave some slop between the big plate and the back of the clutch baket. This gave it some room to move while rotating slow. I kinda know what you're saying about noisy kx's at idle. The two stroke's sound idling is weird. For one you have the exhaust sound, but you can also make out the cylinder and piston purring. And the they both seem to be doing a different pattern. Its the New Noises that are the bad ones. Sounds like something different than what I had. Mine made the noise bad at a slow idle, but was hardly noticeable at a fast idle and past that, or while in gear. Smart idea looking in the oil fill hole for the white collar, but I did have one break, but looked good until I finally removed it. 2 strokes are supposed to be a simple design, but it never seems easy to diagnose minor issues. you have to be ready to work on them, alot. Definately report what you find. You will likely save someone some trial and error with the same issue.

[mustangfury]

a lot of my bikes symptoms sound like what yours did.  The noise is definitely the loudest at idle and then at a fast idle it gets quieter and when riding, it is possibly gone, but i figured i just couldn't hear it due to the other noises like the exhaust. I have a feeling it is something similar to your deal.  I checked again and the noise is definitely coming right around the back of the clutch area.

Also, do you know about that drive sprocket leak I mentioned?

Another question,  when you take out the spacer behind the drive sprocket, if oil is coming out, does that mean the seal is bad.  Something in there is leaking oil onto the chain and my guess is the seal, but i was wondering if oil would come out without the spacer in there even if the seal was good.

[cutting torch]

Does your kick idler gear still have a bushing in it? The '87 I got had lost it's bushing and the snap ring that retained it to the end of the output shaft. It did a bang-up job on the back of the clutch basket!

That's all I can think of that would make a very noticable racket. 

torch

How do i check to see if the bushing is still in there?  What does it look like? Can you show me what it is with a parts diagram or picture?

The idler gear on the left has no bushing, and the one on the right has a bushing. Easy to see here, not so easy to see when things are assembled.



You can also see the marks on the back of the clutch basket from the idler gear flopping around.

If you look at the first pic in this post, the idler gear is the one that you see very little of, between the clutch basket and the kick shaft assembly. If you do pop the right side engine cover to look, you don't need to yank the basket to check the idler gear bushing. All you need to do is pull out the kick shaft assembly, then see if you have a lot of slop in your idler gear. You should not be able to move it up or down, or side to side.

As for the seal and spacer, if you pull out the spacer, it will drool. The spacer is what rides on the seal.

torch