I bought this bike back in Feb. of this year. It had a bad rod knock, so we tore it down and replaced the crankshaft, push rods, and push rod bearings. It is running fine. I can start it, drive it wherever I want to go, but if it's hot, it does not want to re-start. After a bunch of reading here, I decided that the fuel system might be creating a vacuum, so I started poking around. I noticed that the fuel shutoff valve has this vacuum line;
The new fuel shutoff valves do not have the vacuum line;