Bad vibration

[Northern ANdy]

It always vibrated abit through the bars, but just lately at 6krpm its quite severe and leaves the hand numb after 10 minutes. I have thought about bar end weights, but I'd also like to know where this new vibe is coming from. My theory so far is just to wait until something (perhaps crankshaft) snaps in two and then i'll know it was that - or whatever it is that breaks. I know its not speed related, and I know its deffinitely not gearbox related, it doesn't go away if you vary the load either. So just wondered if anyone has a suggestion.

[zimm]

carb balance

[Northern ANdy]

only did them 2000miles ago, do they go out that quick?

[RedexRobB]

Dunno if they go that quick but its worth a try, if you got gauges all it will cost you is a few hours time.

[Northern ANdy]

Dunno if they go that quick but its worth a try, if you got gauges all it will cost you is a few hours time.

yeah I've got the gauges, its the time I cannot spare.

[RedexRobB]

stay up late and do it middle of the night neighbours wont mind

[Northern ANdy]

eeeeeeeeeeeee well I've stuck the vac gauges on it, no better.

[RedexRobB]

lost a wheel balancing weight off the front? What rpm does it do it at? Sounds painful but rev the bike on standstill at the rpm it comes in at and see if you get it, should know then if its engine or chassis related.

Out of interest, where the carbs out by much at all?

[Northern ANdy]

6k rpm its at is resonant frequency, at 5.5k rpm its fine, at 6.75k rpm its fine, its not the wheels because its not related to road speed, only engine rpm. erm I think the left pair of carbs where pulling 1.5psi more vacuum than the right pair, could've been the other way round. But only the centre adjustment was out, 1 & 2 read the same, 3 & 4 read the same, but 2 and 3, and 1 and 4 read differently

[RedexRobB]

Okies, everything tight? Handlebar isnt loose any nut or bolts, engine bolts etc?

[Northern ANdy]

have yet to go round it with a fine toothed comb in honesty. The whole thing vibrates, tank, pegs etc

[masterofinsanity]

could be the tyre out of shape? wheel balancing? lost a weight??

[rover220]

could be the tyre out of shape? wheel balancing? lost a weight??

unilkey as it doenst happen at a set road speed, only a set rev range. however, its always worth checking these bits.

[Northern ANdy]

could be the tyre out of shape? wheel balancing? lost a weight??

its not anything to do with the chassis, Its stayed through this set of tyres just like it was in the last lot. It is an engine related vibe

[carsounds_dan]

checked your tensioner?
could be the camchain shaking about or air stuck underneath your pistons? try an oil change?
cheers
dan