Hello, I picked up a Suzuki Pe 250 I think its a 1980 or 79 but the engine is junk. It seems like the bottom end went but kept running and the play in the bearings caused the flywheel magnets to break off. The bearings are really loose in the case and the engine is just a basket case. But the actual dirtbike is in good shape mechanically and I like the style and size. So what engines could I put in here? I have decent fabrication skills and would not be against putting a 4 stroke in the bike but what should I know to do the swap?