i changed the head gasket, jetting the carbs to stage one, de-baffled the exhaust, and replaced a few bolts in the motor. A few months ago after I jetted the bike it wouldn't run propperly it was sputtering shutting off at low rpm and couldn't go over 100 kms an hr without feeling like I was hitting the rev limiter. I Synced the carbs and the problem was resolved. Now four months later the symptoms have returned except at a lower speed of 50 km per hour and up it feels like, sounds like, and acts like a rev limiter is happening. So I re synced the carbs, and ther was no difference. After a long while of frustration I took it into a mechanic shop ( st onge recreation) where they assumed it was the battery, that was replaced. Then they thought the fuel pump was the problem. Still nothing so they cleaned my carbs removed my jets and re-synced my carbs.. In total they took 600 dollars and three weeks of my time and it came back in the same condition. any Ideas?