Welocome also, I had this problem with an inline though it could happen to V types. The problem was a bent push or the push rod came off from under the rocker arm. Gas was getting in but not getting out. It would POP through the carb when reved up. Its been a long time since this happened. If you timed it and it still does it then take off the valve or push rod cover (side cover) a check for a push rod either major bent or somehow came off the lifter. If it does it constantly and not just occassionaly then its probably the trouble. Just replace the rod. They are great engines and last for years. Tough as nails. H.
