i got a HJR 421 Cub. Im a aircraft mechanic so im mechanically inclined. i got out the military and moved back home. i moved from 3,000 feet to sea level and of course i blew the top end. i'm getting it back together and i went ahead and bumped the compression up to 165psi for AVGAS. i ride mostly wide open trails maybe about twice out of my ride i might have to slow down through a tight spot. so with that said what can i bump my timing to? what should i start with in jetting. and do i need 100percent AVGAS or not? my mods in my sig
ps what else can i do to this thing? i ride with two honda 450 dirtbikes and a modded rm250 and they are still kicking my ass