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Knocking at low rpm

Posted: Mon Oct 05, 2009 5:11 pm
by olie05
I just noticed my bike is doing this:

From a dead stop, warmed up or not, if I let the clutch out slowly and give throttle, from about 1300 rpm to 1600rpm I will hear a quiet knocking sound as I accelerate. I have tried replicating the sound by holding the brake and throttle at around those rpm with varying degrees of load, but it seems to happen the most when i'm just accelerating from a dead stop. It sounds like it might be coming from the left side of the engine.

Also, the sound does not happen at any other RPM range.

I know i need to lube the chain,
I know I need to change oil.

besides these things will there be another source for this knocking sound?

Should I pull the pan and check the rods?

I need some advice on this issue!

Re: Knocking at low rpm

Posted: Mon Oct 05, 2009 5:59 pm
by reelrazor
Is it only when moving (rolling)? Seem like it is tied to the wheelspeed? Suspect your chain/sprocket setup. All it takes is one 'hooked' front sprocket tooth, or one kinked chain link to make a sound like this.

Re: Knocking at low rpm

Posted: Mon Oct 05, 2009 9:50 pm
by olie05
Do i just check for this with the rear wheel up or is it any more involved?

I was eying the 520 chain conversion anyway, so this could be good.

Re: Knocking at low rpm

Posted: Tue Oct 06, 2009 1:08 am
by mossy1200
I take off at 7000rpm so cant help you there.

Re: Knocking at low rpm

Posted: Wed Oct 07, 2009 10:31 pm
by olie05
I took out some of the slack in the chain, lubed it, and the noise seems to have stopped. Could it have been the chain slapping against the swingarm somehow?