i have a 2004 kfx80 i been reading your comments on them , i have taken out the front 2 rollers, and have a ct racing pipe coming in, when i took off the head i noiticed piston chipped and burnt so iam replacing that also, went to a 51mm wisco piston , bike was stock before this , haveing the head milled .030 and porting the exhaust port 3mm on both sides and the top, also, ordered a #90 jet . i was wondering is there anything u would do or not do, didnt want to get to into it, but u know how that goes, started off changing the spark plug then all hell broke loose,lol, i can give some advice i appreciate it, name is raul,,, thank for the help