left pedal vibration on pull/compression transition

A new vibration appeared on my 5th gen that I can feel through the left foot peg. Not as rough as when the chain is too slack. I can feel it when the engine transition from drive to compression. If I maintain the throttle around the point the engine pull or compress, I can feel it: a vibration or grinding. I first suspected the chain but it was tensioned properly. The drive (front) sprocket is due but I cannot see how it can cause this vibration. Is it the chain/sprocket? Could it be a bearing, in the engine or the rear hub? Anyone experienced this? My '84 and my '98 are both falling apart. Time for a '04 asphalt black I have in sight

 

If your front sprocket is bad, change that before you suspect anything else. They are cheap anyways.

 

your chain and sprockets are due for replacement. front sprocket is severely worn, which has damaged your chain, therefore also the rear sprocket.

do all 3 components at once. trust me, I've been there, done that. its NOT FUN.

 

What they said. New chain/sprockets are as good of a feeling as new tires.

 

Thanks for the feedback. There is a consensus. I always change the 3 parts together but when the chain is due (usually the master link is in worse shape than the others). I haven't change it on this bike yet (my first single side swing arm) and this is the first time I experience this behavior.

 

Single sided swingarms are much easier to service and adjust the chain on than standard swingarms.

 

Agree for chain adjustment, I was thinking about the effect of hub bearings failure. Standard wheel bearings are easier to check (or at least, I am more used to).

 

just check for any play in the wheel. I haven't heard of them going bad frequently though.

 

Nice selection on the asphalt black I had the same symptoms once as well, issue was I tightened the chain while the bike was on the center stand so it was to otight. Backed it off and all is well again.

Good luck with your issue.

 

When symptom started, I went to adjust the chain, thinking it was too slack. It was just correct. From the millage done since the previous adjustment, I probably rode it too tight. I just readjusted it on the slack side but its probably too little too late. I fear I damage the drive shaft bearing. I'll gave it a try later when kids will be in bed.

 

How many miles did you ride it when the chain was to tight?

 

Without checking my log book, around 3000 kms. I've been lazy on the maintenance this season.

Removed some tension on the chain and it reduced the strength of the problem but it is still there. I now think it is all explained by the wear in the front sprocket. The grinding is probably when the chain links change side in the sprocket grooves when the tension change side top/bottom for pull/compression.

I'll get a front sprocket to test this assumption and change the 3 altogether next winter. There are still room to stretch the chain. I suspect the previous owner changed the chain and rear sprocket to sell it. Even it it saw more chain links than the rear.

 

Changed the front sprocket and problem gone.