When I was rejetting and romping thru the gears I tended to shift when the yellow light illuminated on the tach, which is 4500 RPM( to low ). The red light illuminates at 6000 RPM as the rev limiter starts to kick in( to high ), so somewhere in between is probably ideal to raise a little hell but not damage anything in the process. Looks like 5200- 5500 RPM is about the 1 O'clock position on the tach and seems about right but I dont know this to be true. Anybody think 5500 RPM is still to high?