Thanks for the reply's lads.. yeah its what i thought, bigger is better. but i thought solid would handle torque better, the frame is thin wall box section yes, but it doesn't need to put up with twisting forces, more bending.. but then big v8 trucks have hollow drive shafts so there is that.
The "supermoto" engine is a Husaberg FC470e motor, 470cc, 45-50bhp depending on carb/tuning and a crap load of torque (1 cylinder). Supermoto is a style of motorcycle. The motor weighs in at about 25-30kg wet (im not a big guy but i can throw it around the shop quite easy with not much effort) so i dont think its THAT much more than the usual 140cc pitbike motors.. The motor is vertical tho so has a smaller footprint than the pitbike motor. For the hub i was thinking to get the rear wheel from a supermoto, remove all the spokes and rim, and then im left with the hub, which carries the sprocket and brake disc, then weld or keyway this to the shaft. The wheels are the unknown, i was gonna get the shaft first and then go with whatever wheels fit. I think normal go kart wheels will be fine, but i plan on perhaps road racing this thing if it comes out well so would like a little more ground clearance than normal as the roads here are not that perfect haha.
