The rotation of the wheels on a bicycle or motorcycle create a gyroscopic affect that is evident when cornering.
The wheels wants to keep going straight.
The Same is true on a kart but to a lesser degree because of the smaller wheels and mass.
I'm wondering what affect the mass of the engine flywheel, crank and clutch may have in impeding the karts ability to turn?
But of course you're leaving out the fact that the juniors are lighter with pretty close to the same tires.So yes it you think about it, that's why Jr. 3 classes are actually carrying more corner speed than UAS karts
I'm probably not smart enough to even think about this but,,,,NO!!!!
My thought is to mount the engine with the crank parallel with the frame not perpendicular to it.
I know this complicates coupling to the rear wheels but that issue can be solved with a differential.