I am working at installing a 4 HP Lawnboy 2-stroke in a bike. I made a rectangular 10 ga. 7X8" plate with a shaft hole and 2 for crankcase mount bolts and 2 for exhaust outlet. I fond I had an old rear exhaust pipe from a 1400 cc Suzuki Intruder that looked like it would crank the exhaust up and back, I made a short stack and welded it to the mount plate. On this I slipped the curvy piece so it would direct the smoke aft. I decided to weld it in place. Darned if I didn't get it 90 degrees off such that the cylinder would be positioned vertically rather than horizontal. Anyhow, on positioning it in a frame I discovered it invaded leg room anyhow. Now I have sawed it off and slicing vees out of one side to weld into slots on other side to make it hug the frame. Haven't done that in years since I used to stick expansion chambers together for friends. UGH !