I started this shoe string budget project by trading some old revolvers for a 500cc Buell Blast. A 38 special Smith & Wesson, a Ruger 357 Vaquero, and a Swiss- made Hamerli 357 (pictured below).
I originally wanted to use a BSA A-65 Lightning frame that I already had (pictured above). I finally decided to use the original Buell frame for two reasons: (1) the oil reservoir is within the frame and didn't want to mess with mounting a tank somewhere to it. (2)The original frame has some extremely sturdy engine mounts because the big single vibrates like hell under about 50mph.