I've been reading about this mod for a year ( I've done it ) and still don't get the theory about solving hot start problems. You need ignition,fuel,and air for an engine to fire. You go out in the morning, set the choke ( fuel enricher ) and the bike starts right up. You ride for a while and shut down the engine. Now it is hard to start. What changed? The AIR, no. The IGNITION,no. The FUEL, YES. The density of the fuel changed. It is now more vaporized. It seems to me the hot start problem is only fuel related. I can see where changing the air gap helps in some ways but not in helping hot starts. Ok, I'll listen.