vibration

[trevf]

my suzuki gsx 750f has just started to develop a severe vibration at 140kph. It is good up to that speed then it shakes that much it is like the bars are going to get ripped from your hands. I have checked tyres for buldges and head bearings-any sugestions

[marty]

maybe it's possessed and knows the new '40k over then you're walking' rule

[merv]

Has anything happened to the bike that is likely to have caused something - like did you hit a high ramp edge or anything like that which might have damaged a rim?

You say it shakes - is that side to side so its trying to tank slap or does it shake in the vertical direction.

Besides the things you have checked it could be bent rim front or back or a swingarm problem if the steering head is OK. Put the bike on the stand and rotate the wheels checking they are still straight like they ought to be. Also give the rear wheel a good pull back and forth sideways to check the swing arm bearings aren't sloppy.

[Marmoot]

Wheels+tyres need re-balancing.
Most probably because balance weight got off.

Check and rebalance wheels.

Also, check threads to see if you need to change tyres while you're at it.