My WR400 appears to top out at 90 mph. It seems to have plenty of power but cuts out at 90 mph. I am running 27" Dunlops with 15/50 gears (front to rear teeth). In 5th gear (.84 ratio) this translates to 10,000 engine RPMs to turn the rear wheel 3520 times per minute, the speed necessary for 90 MPH. Is my bike cutting out at 90 MPH, (10,000 RPMs) because of a REV limiter?