Does anyone have any idea what could be causing this. Whenever I go over 125 KM/hr, I get this pulsing vibration. It is not a constant vibration. The bike shakes about every 2 seconds. Could this be that the wheels are not balanced properly? When my new tires were put on about 8,000KM ago, they were not electronically balanced. I am running with 36 psi front and back (don't know how accurate my digital gauge is).
Can you tell where the vibration feels to originate? Are the handlebars shaking side to side, or is it thumping from under the seat, the front forks oscillating up and down, looseness in the frame, hammering in the motor, does it all the time, only on straights, only in curves, etc.
If it just started vibrating when the new tires were installed.........I think you have the cause. You say that was only 8 kilometers ago? You must live close to the dealer! You must mean 800 kms??
I used to get a pulse (more of a sound than a feeling though) about 1 sec apart at exactly 4000 rpm, Perhaps yours is the same kind of thing? Check to see if it's speed or rpm related.
I would get over that speed, pull the clutch in and coast just to make sure it's not an engine vibration. If you haven't hit anything to bend a rim, I would suspect the tires. Everytime I've had a vibration, it's been the tires. Just my two cents...