Output Shaft (Countershaft) Bearing Noise?

[FJ1100mjk]

I've been having what I thought was a rear wheel bearing going bad, but after swapping the suspect wheel out with a known good one, the noise persists. It's kind of hard to detect where it is coming from, but I think that it is coming from/through the output shaft. It will do it on the centerstand when you rotate the rear wheel, and when going slow while riding/coasting in first gear. It sounds like a knocking or clunking noise, that rises then falls, that I think is due to uneven drive chain tension throughout its length. I swapped chains too, and it doesn't help. Both front and rear sprockets are in great shape. There's no real roughness feeling through the rear wheel when rotating it with your hand on it, and I've been riding the bike and not noticing/feeling anything weird, other than when I'm going real slow like in a parking lot, or pushing out of the garage. It's like something is binding slightly then releasing. Repeatedly.

Has anyone else ever had this kind of noise going on and traced it to something in the engine? If so what you found, let me know what you did.

I was looking at the Factory Service Manual, and it appears that I might have a shot at replacing the output shaft ("main axle") bearing without taking the engine out. The book's not saying that it can be done that way though. I'm wondering just by the pictures that are shown.

I have a 700 mile ride coming up this weekend, and I am going for it, and will await winter for any repairs.

Thanks in advance for your feedback, advice, or help.

Marty

[movenon]

I had a knocking noise, sounded like it was coming from down in the front sprocket area once after I installed a new chain. And found out it was the chain way to tight.  I had it adjusted as per the Yamaha spec's BUT I had converted the rear wheel and installed new dog bones.  The travel range changed and I had to loosen up the chain a lot.  My only suggestion is to loosen up the chain a lot and take her for a short ride. 
I could hear mine knock clearly idling / coasting in a parking lot but at speed I couldn't hear it.

Probably not much help but that's my story. 
George 

[fj johnnie]

 I had a noise like that once too. It turned out to be the sprocket on the output shaft.

[FJ1100mjk]

Guys:

Thanks for the replies.

I have swapped to both a rear wheel and a chain from a bike that didn't exhibit the sounds that are on the bike that they are now installed on. The front sprocket was not swapped, but i had taken the sprocket cover off to inspect and try to determine where the sound is coming from. The front sprocket looks fine, no real wear or hooked teeth present. I guess that I can remove the sprocket, and see if there's anything going on, but I'm reluctant to, since it appears fine.

Any other ideas, or reports of these noises and repairs from others?

Thanks.
Marty

[ribbert]

Any other ideas, or reports of these noises and repairs from others?

Thanks.
Marty

What you describe is a classic tight spot in the chain.

Noel

[FJ1100mjk]

What you describe is a classic tight spot in the chain.

Noel

Thanks. However, I don't understand why if I switch a chain (and rear wheel too) from one bike that doesn't make the noise, to another, then that one makes the noise, that it's the chain making the noise though.

Looks like I have some more investigating to do, but after my riding this weekend is done. I'll run the chain looser too.

[fj johnnie]

 Just because you think the countershaft sprocket looks fine doesn't mean it is. I would swap it and see. When I changed mine the noise went away. I am told those bearings can fail,  however it is not that common. Randy has those sprockets at a very reasonable price too.

[oldktmdude]

I am told those bearings can fail,  however it is not that common. Randy has those sprockets at a very reasonable price too.

The most common cause of output shaft bearing failure is over-tightening of the drive chain. If you are guilty of this, you may have a bearing issue. Having said that, I think that a tight chain link or an out of shape counter sprocket is most likely the problem. Hope you sort it out soon.  Regards, Pete.

[FJ1100mjk]

I am told those bearings can fail,  however it is not that common. Randy has those sprockets at a very reasonable price too.

The most common cause of output shaft bearing failure is over-tightening of the drive chain. If you are guilty of this, you may have a bearing issue. Having said that, I think that a tight chain link or an out of shape counter sprocket is most likely the problem. Hope you sort it out soon.  Regards, Pete.

Thanks.

I'm fastidious when it comes chain care, and versed over the years on the its nuances. However, it's hard to say what care the driveline had before I took ownership of the bike.

I can pick up a new CS sprocket, and another FJ1100 that I recently acquired, has a new chain on it (grey/white packing grease is still on it). Between those two items, I should be able to track down the source(s) of the noise.

Marty

[FJ1100mjk]

After mining the Internet for other motorcyclists who experienced the same noises, one reply from an apparently knowledgeable person, stated that if the bike was rolled backwards and the noise was louder, that it may be due to hooked teeth on the countershaft sprocket. I felt that when I inspected the sprocket before, that it looked fine, but thought what the heck before I threw the towel in on the bike. At least for the rest of this riding season.

I took the countershaft cover back off the engine to inspect the sprocket, and upon closer scrutiny, that yes, the teeth were indeed hooked over. Slightly. So, aha! But, that's not all...

So, I figured that I'd swap out a countershaft sprocket from one of my other two FJs, then see if the noises went away. Well, I had large sockets, including a like new, shiny 30mm from a previous one-time, need-it-right-now use, but not a 36mm one to fit the sprocket nut, but luckily the local auto parts store down the street did. Wallet $11.87 lighter, I'm back at home. I bend back the locking tabs on nut's keeper, put a piece of wood between the chain and rear sprocket to keep it from moving, apply the new socket to the countershaft sprocket's nut with a breaker bar, grit my teeth for the big effort to break the nut loose, and to my surprise, the nut is barely tight!

A loose nut is what someone else had found on one of their bikes on another forum too, that was causing clicking and knocking noises.

I tightened the nut, no more noises. 

New countershaft sprocket, nut locking washer, chain (a good one), and rear sprocket coming over the winter, before riding season 2015. 

[FJ_Hooligan]

Excellent fix!  Don't you just love it when a potentially expensive repair turns out to be something trivial?

[FJ1100mjk]

Excellent fix!  Don't you just love it when a potentially expensive repair turns out to be something trivial?

Thanks. I gotta tell you. I am quite happy with the outcome.

This particular FJ was the first one that I bought, and brought back to life, so I'm kind of attached to it. Not sure if any other owner feels that way about theirs. Yea, right.

I was bummed out by what I thought was a problem I wasn't going to deal with, or bother putting the money into it. All's goood now.