A simple answer for those of us without a tachometer, is to just use a felt pen to mark the max shift points on the the speedometer glass. (After finding them with the rev limiter.) For me (TBA with 17 tooth front sprocket) it is 30, 60, and 80 mph for the first three shifts. That gets me real close to the rev limiter without ever hitting it anymore. Anyway, the torque and horsepower curves don't continue to increase at the top end so I might as well shift, since the RPMs in the lower gear are still producing approximately the same torque and horsepower there also. To hit the rev limiter would just slow me down.
