Thanks for all the kind remarks. It is a product of my design. All drawn in CAD. Most parts are CNC'd. There was a 6 foot length of 6 inch dia. CRS, hence the H-D style built-up "crank". Lots of 10-32 SHCS hold the crank parts together. Rubber band determines rpm based upon # of wraps.(band breaks, engine stops!) Balancing was a good guess and is probably smooth because the flywheels might be too heavy. Will experiment with lighter flywheels and finer threads on needle valve.The ignition is GM points timing 12V coil(in box) off crank.(will eventually use switch on pushrod to save battery). Starter gear is same as crank gear so, is 1 to 1 ratio. "Electric" starter won't appeal to the purists, but I just wanted to see it run. All gears designed in CAD, then CNC'd. See my gear procedures on YT. Designed cam with 3 different profiles to get what I wanted and may do one more for more duration, maybe not so much lift.
Hard to describe the feeling when the thing first pops, and then, again, when YOU are the one cutting the ignition to make it stop instead of it stopping itself. I'll take some pics as I build more engines.