betty, there is a mod at the original QFM mod site that lets you use a bit-racer 7 tooth pinion with any bcg gear set. it is the motor balance mod, basically you need two matching flat pointed screws that fit into the motor bay of the bcg. screw em in untill they angle the motor to get the right amount of mesh between the gears…
that and do a bit of shaving around where the pinion goes…
one of my bits run an 8 tooth pinoin! niiice top speed!!!
http://www.geocities.com/bettyk3332003/ferrarijump10.JPG
in this pic did it land the flip?
nice vert!!!