http://www.gbone1.force9.co.uk/rw99/pic ... ential.jpg

The differential used in one of the firestorm encarnations. There's a reason that no one else (as far as I'm aware) has used a similar setup, they are difficult to engineer!

A few other problems jump to mind with a mini moto engine,

- Being an engine it doesn't have a great deal of torque at low revs and so will always have a delay in getting a robot up to speed
- You will have to have a gearbox to allow the robot to go in reverse
- You will need to have a way of remotely starting the engine as it will most likely stall in the arena (believe me, I know how likely engines stall in a robot arena)
- You may have trouble running it at a competition as there aren't many venues happy to have internal combustion engines running due to the exhaust fumes.

The other possible way to use it would be to have a single powered rear axle and servo steered wheel at the front (mighty mouse style)?