clunking nose

[sammy347]

hi all when i was out for a spin when in low speed i sometimes get thi clunking sound seems to be at the rear of the bike, i thought it was a drive chain noise. there are only new chain and sprockets on it, it still did the same with the old ones, wondering what it could be. if anyone knows be glad to listen, sammy

[Pete.L]

Depends on the type of clucking.
Two things I would check immediately, The crush rubbers in the rear wheel and the suspension dog and bone bearings. Both are known weaknesses.
Get the bike up on a stand with the rear wheel off the ground. Try lifting the wheel up and down, if there is any movement the suspension bearings in the dog and bone might be giving up.
To check the crush rubbers, keep the bike on the stand with the rear wheel off the ground, put the bike in gear and then try rotating the wheel back and forth. If there is more movement than just the slack in the chain watch the rear sprocket and see if it looks like its rotating in the wheel hub. If you have movement, it's the crush rubbers

[sammy347]

cheers pete, will check it the way you say tomorrow

[tony.mon]

Is this an occasional dull "thunk" noise, not related to revs or speed? Does the engine die momentarily when it happens, then pick up again?
If so it's the carb fart or carb cough, they all do it, nothing to worry about.

[sammy347]

im thinking along your lines tony i have tried what pete suggested there is no play in the wheel at all and the only play is the chain slack, i have just noticed the chain tensioners one is ajusted more than the other, the wheel looks straight, i measured from the middle of the swingarm bolt to the middle of the back axle bolt ,they are the same distance, i just have a feeling i have a link to much on the chain.

[tony.mon]

The swingarm is a welded construction and won't always be exactly straight. Use a piece of string touch the rear part of the back tyre, pull it forward to the front of the bike and move it until the string just touched the forward part of the rear tyre. Now observe the gap between the string and the front tyre. Do the same the other side, if the gap at the front tyre is the same both sides then the rear wheel is straight, no matter what the adjuster position is.
It's easier with two people.

A bit of wood does the same job, but that can be warped...
I use a length of curtain rod, as it's nice and straight.

[sammy347]

Ok Tony is it 42 links for these

[tony.mon]

Dunno. I usually order a long chain and cut to size.
Haynes or workshop manual will tell you.
It depends on what sprocket sizes you're running.
I rarely ran standard.

[sirch345]

The main drive chain standard length is 102 links. Standard sprockets are: Front 16 teeth and Rear 41 teeth,

Chris.