What rpm's are you shifting at when racing?

The 2003 bike makes peak power at about 12,500 rpm, and you should have a shift soon afterward, unless you are on a bit of track that calls for overrev. There is little power above 14,000 rpm.

For a dyno chart, check out this thread.

So it would be optimal to set the shift light at 13500rpm or is it better to shift near redline so the rpm's stay up in the next gear?

You want to keep the revs between peak power and peak torque. On this bike, upshifting near peak power drops the revs to near peak torque.

But the tach reads a bit higher than the actual engine speed that the dyno chart shows. The bike likely peaks closer to 13,500 rpm on the tach.

You can dyno your bike and make a note of the tach at peak power. You want to set the shift light there. In a pinch, 13,500 rpm is arguably close enough.

Guess what? Rob's right as usual. 13,500 is a good area. My '98 (and pretty much every other 600 I've owned - R6, Gixxer, and 2 previous 6R's) all needed to be wailed to just before redline. The 636 produces a different power curve, even with an aftermarket exhaust fitted, and needs to be shifted a good bit short of redline or you're gonna hit a wall where the power drops off, if not the limiter. Even shifting at 13,500, you're going to be coming right back near peak in the next gear in no time, and that's the best way to quick progress on the '03s...