I have the socket for 2F probably for F. I also have the bracket for the bumper for the crank to go in.
The threaded rod looks like a fine design, as you could really cake the threads with grease, and I'm into making threads more than burning welds, but a spot weld on it would keep it from...
I think that the kick-back is from ignition occurring too early on the compression stroke. Four-stroke engine stuff, you know. Any other ideas on how to spin it backwards?