Engine clunking only when clutch disengaged

kevin567

Registered
I just bought an 07 busa with 26,000mi. I noticed some clunking noise in the engine when I start it cold. The noise is like a bunch of marbles in a plastic container... no sharp pings, just dull "klug-klug....klug". If I engage the clutch the clunking goes away. When I'm cruising at speed (any gear) I can feel the clunking in my feet (I'm sure the noise would be there too but the wind and engine noise drown it out!). The bike accelerates very smoothly, no hesitation... just the 'tapping' I feel in the pegs.

Is this something I should be concerned about? I don't know the service history, but the fluids look clean and full, no smoke or bad smells from the engine/exhaust, and I'm averaging 38mpg.

The bike is stock except for a K&N, and the plugs are new.

Any advice is greatly appreciated!
 
It is possible the springs in the clutch basket are worn. If you do not drag race the bike you would never notice it. While drag racing the bike would buck and lurch violently off the line.

Pull the clutch apart, it is not difficult if you have any mechanical experience. Check the springs in the back of the clutch basket. If they are very loose you may have found your problem. They are not supposed to move at all.
 
It is possible the springs in the clutch basket are worn. If you do not drag race the bike you would never notice it. While drag racing the bike would buck and lurch violently off the line.

Pull the clutch apart, it is not difficult if you have any mechanical experience. Check the springs in the back of the clutch basket. If they are very loose you may have found your problem. They are not supposed to move at all.

You were right on the money! Five out of the six basket springs are loose, so I'll get them replaced. I don't drag race, but I don't like the noise!

Would that cause the loud CLUNK when I put it in first gear?
 
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