Bad Vibrations please help
 

my bikes still vibrating to the point where i dont like going over 50mph for more than short bursts. the engine pulls strongly but my ankles and shins can't take the vibrations. that and my mechanically sympathetic mind

I've had a couple of old XT's & an XR before and yes they do vibrate but this is excessive.

All engine mounts & swing arm pivot are torqued up correctly. and I've checked all nuts and bolts are tight like crank balance shaft and flywheel/magneto. the Tank is sat on its rubbers properly.

the bikes fine up to about 45mph then it starts the vibes. pull the clutch in and coast and vibes go.

The bike - a 34L, has done 54,000 indicated miles although who knows what the true figure is.

the engine was noisy but since the top end rebuild it sounds really sweet.

could it be the bottom end even though it sounds OK?

what can I check??????

please help as the vibes are really stopping me enjoying the bike.


cheers

has it always vibrated or just started recently ?

If you're convinced the motor's fine then how about the running gear - has a balance weight popped off a wheel, or the chain developed a tight spot, for example?

i think if a weight had came off the wheel it would still vibrate with clutch in.
i was thinking maybe if its always vibrated there could be a tooth out on the balance shaft gear ?

what gear are you in it could be in the gearbox are the same vibes there at high revs in lower gears :confused1:

DOH! I should've read the post more closely - apologies - are there heavy vibes (blimey, i sound like a hippy...) up to the 45mph threshold? Wouldn't a balancer problem be at all engine speeds... this is a real head-scratcher :confused1:

yes, it does it in all gears:(

do you mean the balance shaft gear could be a tooth out? how do you check that?

You will have to take the clutch cover off and there is a punch mark on the balance cog it has to line up with the punch mark on the cog it's connected to

I would also of thought if it was that it would vibrate in neutral if you revved it as well but I could be wrong?

well, i've revved it when coasting with the clutch in and the vibes come with the revs.

now that puts it into the realm of balance shaft problem

Have you checked the engine oil for metal shavings? What happens if you rev the bike in neutral? Could the clutch basket be somehow loose or out of balance?


I know this is not what you want to hear, but I think you should open up the engine now. This sounds like something is taking a hammering, I think you should not ride the bike like this. I am not an expert in your bike, but my advice is to check the balance shaft as wolfzero said, and bearings in general, but also check if the clutch basket is wobbling, or if the flywheel is wobbling.

thanks for all the help on this,

balance shaft teeth line up OK

http://lh5.ggpht.com/_aJzSBN66Sc0/Sk...0/P4280230.JPG

but I do have a bit of movement on the clutch housing, presume there shouldn't be any play?
http://lh4.ggpht.com/_aJzSBN66Sc0/Sk...h%20basket.JPG

whats the best way (no special tools) to hold the clutch so that i can undo the nut and investigate

thanks
andy

I tried to take mine off without the proper tool and it cost me dear :( very easy to smash outer basket,windy gun is best option without clutch holding tool IMO