I do not think you can install a 6 th gear,if you could your ratios would be off,what I mean by this is that the gears have a ratio to climb a scale evenly somewhat,if you add a 6 th gear the ratios will be uneven.It is like dividing 1 by 6,or 1 by 5,there is quite a difference.This bad boy is barely working in fifth gear,just have fun.I have a 2002 bandit 1200 .If you want to bring your RPM down just install a smaller sprocket(3 teeth less) on the back or one tooth bigger on the front.A very cheap way compared to insatlling a 6 th gear.