CRF's Only Forums

I've had a 04 150F for a little over a year now, and have been running stock intake, engine, and exaust (w/o baffles) ever since i bought it. It bogs and pops alot, and i'd really like to know a way to get power without spending much over about $300. Please help.

a pipe and a sproket 428

i would have said BIG BORE KIT but it is like 375 but you need the new carb, then new cam shaft, and the D-section pipe

$4299 will get you a crf 150r
$6349 will get you a crf 250r

there is not a lot more hp to be gained out of one of these motors. You can get it up from 12 to mid 15's.
And yes 15 is more fun than 12 but you would be better off saving the cash for your next bike.

does the renthal 428 kit actually give you better acceleration and power? i've been thinking about getting one because my chain and sprockets are getting wore anyway, but i'm not sure about the non-o-ring 428 chain.

428 give the same ratio than the 520 gear stock

but the sprocket of the 428 are lighter and bigger, it is more easy for the bike to move it than the 520, also you win 2hp with a 428 sprocket kit

you might also consider getting the power up kit for the carb. it does help, that and adjusting the fuel screw will help get rid of the pop on decel. you can get this from Honda, needle and jet runs around $25-30 from Honda.