Hearing a "clunk" at low speeds...

[J. Kidd]

When I start off slow in first gear or even when I shift to second and continue to go slow, I'm hearing a clunk. I don't hear it if I take off hard or in the higher gears, its usually in the conditions listed above.

Any thoughts? Tranny issue, chain issue, bolts loose somewhere???

Thanks.

[Black_peter]

clunk clunk clunk clunk clunk clunk
Or just
clunk??

You could have something loose (scary)
that shifts as tension takes up the lash in the
drive train..
Or maybe blown out cush drive..

I would get it on the center stand and
(with the engine OFF!!)
put it in first.
rotate the wheel and see if you can duplicate the sound..
Forward and back...

You could also try doing it in nutral..

[J. Kidd]

Its usually just one or two clunks as I get going. I've tried accelerating and decelerating to see if I could get it to happen again (due to driveline slack being taken up) and it won't duplicate.

[Black_peter]

Hmmm well then maybe the best bet is to try it on the centerstand.. it might be 0MPH to 5MPH problem...

[Black]

I have the exact same problem. 3-4 or 5 clunks in 1st and 2nd. It sounds like the tranny I think. It sounds the same as if you don't get a perfect 2nd gear shift and you hear the "clunk" on there, but this noise is while driving, not shifting.

I used to oil the chain and it went away for alittle while, but I think that's all in my mind.

-sam

[The CyberPoet]

(A) Bike transmissions are designed to be slammed home with a quick, clean snap. Unlike car trannies which often have planetary gears, a motorcycle uses a sequential gear box, which needs that type of snap to engage the teeth firmly on the first pass. Clunks often happen to riders who don't engage the gears firmly and fast, because their foot motion leaves the gear teeth dancing over each other until they finally mate (the clunk). The problem with this is that as the gear teeth dance over each other, they damage each other's teeth.

(B) Bad chains (faulty links), bad sprockets and mis-aligned rear wheels can also cause this kind of noise, as the chain sits high on a sprocket tooth and then suddenly snaps downwards instead of engaging smoothly at the first mesh. Always replace sprockets and chains at the same time, and check your chain for both correct amounts of play (1 to 1.1" is ideal; factory spec is 0.8 to 1.2" of play). For more info on failing chains, why they fail, how to test for failure, etc., see my webpage:
How to understand, evaluate, comprehend motorcycle drive chain wear, stretch, aging, maintenance and replacement, at MotorcycleAnchor.com, makers of the best above-ground motorcycle security ground anchors, built 100% in the USA!

(C) Bad cush drive. Under the rear sprocket is a set of rubber spacers called the cush. It's job is to help cushion drive-line lash so the tranny and chain doesn't have to take a lot of instantaneous forces. As the cush parts age, the rubber hardens and stops doing it's job of cushioning, permitting more force to be transmitted back into the tranny (possibly damaging the main output shaft) and causing the chain & sprockets to wear at an accelerated rate. My personal opinion is that the cush needs to be changed every 5th year in general (being made of similar rubbers to tire carcasses, the VOC's in the cush probably dry out in about the same time frame as a tire's VOC's).

Cheers
=-= The CyberPoet