i was reading an article about 4 stroke hop ups, and it said that most mods (including high compression) require richer jetting. well, i think they are wrong. after i put in my 13.5:1 piston my bike wanted less fuel. the bike had a rich spot until i leaned the fuel screw from 2 1/2 turns to 1 3/4 turns out, at which point the idle would hang a little but there was no decel popping. how do i tune the jetting now? these rich and lean spots dont make sense to me.