Strange noise

[anonymous-user]

Hi all, my little ybr125 has started making a strange noise and wondered if any of you might know what it could be. The noise is best described as a whirring/chuffing that isn't constant but increases/decreases with speed every few revolutions of the back wheel. I've tried slowing down both in gear and coasting with the bike in neutral and it still does it so don't think it's gearbox related. The noise seem to be coming from the left side when sitting on the bike. Anyone got any suggestions?

[Rubin215]

Is the chain lubricated and adjusted properly?

[trickywoo]

My guess would be chain or sprockets.

Check for tension and any stiff links.

Also check for play in the rear sprocket. Give it a pull top and bottom. It shouldn’t have any movement under light pressure and definitely no clicking which would indicate a worn sprocket carrier bearing.

If that all checks out suspect rear wheel bearing. Again pull the wheel top and bottom. Shouldn’t be any movement.

[Steve Bass]

trickywoo said:

My guess would be chain or sprockets.

Check for tension and any stiff links.

Also check for play in the rear sprocket. Give it a pull top and bottom. It shouldn’t have any movement under light pressure and definitely no clicking which would indicate a worn sprocket carrier bearing.

If that all checks out suspect rear wheel bearing. Again pull the wheel top and bottom. Shouldn’t be any movement.

Check bearings and cush drives

[anonymous-user]

Thanks for the advice, adjusted the tension for the chain and all good now. However the clutch cable snapped half a mile from home this evening. Bloody bikes!