if you stick a faster motor in it generally you should tweak the gearing go down in pinion size, reduces chance of overheating etc ( please anyone correct me if ive got it wrong way round ). although can you adjust the motor position in the grasshopper to allow for correct gear meshing, i cant remember?
either way if your just doing it for kicks stick an 11 turn motor in it and have fun...but if you want a better chance of controlling the thing go with a 15+ turn motor!
have fun
