My 87' FZR1000 has a strong vibration at 4500rpm in all gears and neutral, it passes as soon as i pass this rev range. I suspect the problem is not gearbox related, any pointers ??

My old XJ750 used to do the very same thing @ the same revs

I think I narrowed the culprit down to a camchain tensioner issue along with a need for a good carb balancing.

HTH

BTW...... to the Forum

all 4 cylinder bikes will vibrate at a certain revs,if the carbs are balanced it is better to adjust your speed to suit or alter the gearing

the old pre-exup engine is a bit more vibrating than the newer one... and still the t-ace owners keep saying that it vibrates. nothing really you can do to it. carb balancing as said before.

also a bit of help if you change the handlebar grips to "soft" ones. and add some massive antivibration endbars. no carbon here

Just get use to it and speed up... After 140km/h it will end

Just get use to it and speed up... After 140km/h it will end 

Yeah dude ive been running around at 140+ ( plod wont be happy, but then again who give a rats ! )