[Turbo DV8]

After a ride, I was rolling my bike, with 5800 miles, into the garage, and I heard a repeating, soft clunking noise for the first time. Sounded like it could be coming from front or rear sprocket area, but favored front. The next day, with cold drive train, no clunking. But after a ride, the clunking was back, but a little worse. Removing the front sprocket cover, the clunk occurred at the same point in each revolution of the front sprocket. The sprocket sort of floats on the output shaft a tiny bit, and I took it off to inspect. The mating teeth were completely devoid of any lubrication, and there was rust beginning on several of the teeth, even though the bike has seen not a drop of water (wash or rain) since I bought it new. I degreased and derusted the sprocket and output shaft, and reassembled with a thin layer of moly lube between the mating splines. Now no more clunking after a ride. Just thought someone might find this useful.

 

[MotoMike]

Interesting that it was only making the noise when the engine was hot.

 

[Ramza21]

After a ride, I was rolling my bike, with 5800 miles, into the garage, and I heard a repeating, soft clunking noise for the first time. Sounded like it could be coming from front or rear sprocket area, but favored front. The next day, with cold oil, no clunking. But after a ride, the clunking was back, but a little worse. Removing the front sprocket cover, the clunk occurred at the same point in each revolution of the front sprocket. The sprocket sort of floats on the output shaft a tiny bit, and I took it off to inspect. The mating teeth were completely devoid of any lubrication, and there was rust beginning on several of the teeth, even though the bike has seen not a drop of water (wash or rain) since I bought it new. I degreased and derusted the sprocket and output shaft, and reassembled with a thin layer of moly lube between the mating splines. Now no more clunking after a ride. Just thought someone might find this useful.

Any pics of the area?

 

[TX_Dj]

I agree with mike, that it's interesting it only seemed to be when hot...


My immediate suspicion was a too-tight or binding spot on your chain, but those would have changed when you slacked out the chain to remove the sprocket and if you lubed it when it went back together.

 

[Turbo DV8]

Interesting that it was only making the noise when the engine was hot.

Maybe some parts in question had slightly different clearances between hot and cold, enough to make a difference? I should mention my hearing is ridiculously keen, for better or worse. My CX500 rear drive splines made a similar, but much worse, noise when they got dry, and it was also quite a bit louder when the drive was warm vs cold.

 

[Turbo DV8]

I agree with mike, that it's interesting it only seemed to be when hot...


My immediate suspicion was a too-tight or binding spot on your chain, but those would have changed when you slacked out the chain to remove the sprocket and if you lubed it when it went back together.

But the clunk occurred at exactly the same point of rotation of the front sprocket, which in my mind pointed more toward sprocket or (gulp) output shaft bearing. When I removed the chain and sprocket and rotated the shaft by hand, no clunking, and it was butter smooth. That's when I started to look closer at the sprocket mating teeth.

 

[MotoMike]

I gave the output shaft splines on all my bikes a shot of chain lube, as a preventive measure. Thanks again to the OP for the heads up on this issue!