I'd be looking at the needle bearing, and the bushing and thrust washer behind the clutch basket.
This bearing only come into play when the engine is running and the clutch is disengaged. When the bike is moving normally in gear, and the clutch lever is released, there is no movement of this bearing, and no noise from it.
__________________
Ron in Cincinnati
Wish I didn't know now what I didn't know then.
.........Bob Seger
I think that the poster assumed it was a clutch problem because of the noise coming and going with the engage/release of the clutch, but the clutch is not the actual problem. When the belt is under load, the pulley is quiet, but under coast, the pulley is free to slap back and forth on the output shaft thus making the noise.
Tightening the pulley nut does no good as the nut only stops the pulley from falling off. It does not tighten the pulley on the output shaft.
Simply removing the front pulley would confirm or rule out this problem.
Anyone who can hear bearings rolling in an oil bath should be working for SETI.
Just saw a 900 Custom late last week getting a new output shaft and pulley so the OP certainly doesn't have the first or only. This was the second time for this bike but they chose to only replace the pulley the first time and it ran quite a while.
PM although the needle bearing behind the clutch is plausible I wonder. Has anyone really witnessed this before? Sure makes me wonder?
Just saw a 900 Custom late last week getting a new output shaft and pulley so the OP certainly doesn't have the first or only. This was the second time for this bike but they chose to only replace the pulley the first time and it ran quite a while.
Unless Kawasaki has come out with a tech bulletin on this problem saying otherwise, I would be applying this compound on every repair:
Absolutely!
In the pic, it looks like they were picturing what it looked like if not applied to the outer race of that bearing. But that would be a bore that was machined or worn too loose to support a bearing.
__________________
Ron in Cincinnati
Wish I didn't know now what I didn't know then.
.........Bob Seger
That compound is to prevent metal fretting, such as what seems to be happening between the pulley and the output shaft. There have been reports of what appears to be rust and corrosion , with subsequent wear, between these two parts when taken apart. That is a sign of metal fretting.
The splines must fit tightly without being an interference fit.
If there is ANY movement between pulley and shaft, possibly combined with a belt that is too tight, and you have a formula for fretting to occur.
It is not for components that are moving, it is for compnents that fit together and experience movement with each other almost on a microscopic scale.
I am not sure if it is similar to anti-seize... probably moly grease with a high percentage of moly might be a substitute, but application of the correct compound can never go wrong.
That compound is to prevent metal fretting, such as what seems to be happening between the pulley and the output shaft. There have been reports of what appears to be rust and corrosion , with subsequent wear, between these two parts when taken apart. That is a sign of metal fretting.
The splines must fit tightly without being an interference fit.
If there is ANY movement between pulley and shaft, possibly combined with a belt that is too tight, and you have a formula for fretting to occur.
It is not for components that are moving, it is for compnents that fit together and experience movement with each other almost on a microscopic scale.
I am not sure if it is similar to anti-seize... probably moly grease with a high percentage of moly might be a substitute, but application of the correct compound can never go wrong.
Probably a good annual winter maintenance project for us with belt drives!
__________________
Ron in Cincinnati
Wish I didn't know now what I didn't know then.
.........Bob Seger
Probably a good annual winter maintenance project for us with belt drives!
I just cannot see a downside to that idea.
The alternative is a teardown, which is never fun or entertaining.
If you have ever had occasion to change the ball bearings on a mechanical contraption and you find a lot of orange/red rust on the shaft and bearing, that may be an example of fretting between the shaft and the bearing race. Next thing that happens is shaft/bearing housing, and bearing race erode, now one or both are loose and you spin the bearing in the housing, or the bearing is almost impossible to remove. Of course, a seized bearing can do the same thing, but that is a different topic.