im getting a lot of high frequency vibration through the bars and sometimes pegs, at aboout 90mph > gets worse the higher the speed.

wheels have just been balanced with new tyres, everything seems to be tightened, have made the front end stiffer but this still does not seem normal !!!!!

can anyone help, - is it just that the carbs need balancing (are the carbs, very sensitive to balancing because i've just done them and it tick over fine and runs at low speed v. smoothly. ????????

any suggestions what to look for...

Check your chain & sprockets. Chain could be to tight or sprockets could be worn.

if none of the above get rid of the problem,get your motor mount bolts retorqued to specs...it works!

:yesnod

does it feel like you're only running on 3 cylinders?

no it runs on full power no problems, but it seems to be there more on some occasions than others, weard !!

I'v tightened the engine mounts, calipers, wheels etc. and other parts, but havnt checked the head bearing yet, for tightness - could it be the head bearing is loose !

Definitely check the head bearing. If it was the head bearings you would probably feel a knock when you jam the front brake on or go over bumpy roads. I think mine has only been actually adjusted once or maybe twice in 14.5k miles. It was checked at each service and they put a pen marker on it so it would show if there was any movement.

I asked about the 3 cylinders because I was thinking of something else ....but it doesn't sound the same as your problem.

took bike to dealer today, asked them to check h/bearings--- they said they were very loose! They tightened them up and its made shit loads of difference...

Good news.

Get yourself a hoofing great socket so you can do it yourself next time (I've got one but its still too shiny to lend to anyone yet :o)

Glad your fixed it. If anyone else is having the same problem and finds tightening head bearings doesnt solve it then, i had a similar problem, which turned out was just down to the carb mixtures. The bike was running a bit too rich and this caused vibrations at about 4000->5000rpm.