I say your tach  is messed up. Some of the best Zillas are only going past 8000 range. Then other fall off before 8,000.

I'll take that a lot easier than a straight bash. I did some digging around for some info on the tach and they don't have many good reviews at all and dad said it read awful high on my little brothers apex too. Somewhere close to 10k and had a delay to it, like it climbed on decel instead of right when you rev it but it didn't have the lag on the 500 motor.