03 crf450 top-end time...

[dangle]

Well it's time to rebuild the crf.. I've never rebuilt a 4-stroke but totally rebuilt my banshee without any hangups... Need to know what all do I need to buy and which piston do you guys run... was thinking up bumpin up to a 12.5-1 JE piston? I figure I need valve shims and everything else will come in the rebuild kit? It's bone stock....never been rebuilt b4 :D ...


Mike

[2muchquad]

having worked on the hondas,i would personally pull one of the valves and inspect them.if they are cupped pretty bad you may as well replace them.usually when they are first shimmed,valve adjustments will be a lot more frequent.the early crf450s ate them regularly.the quick fix is the stainless steel valves.BUT the best way is new stainless valves along with a set of stiffer springs.the stock springs dont hold the valves against the camshaft allowing them to "slam" into the seats.i have known guys to go through 3 sets in a season of riding.no bs.a wiseco piston could be a cheaper alternative to the je,both are good though.i run the 13.5 compression in my yzf,stock was 12.5 to 1.i think 11.9 to 1 was stock on the honda that year.if you have never worked on a 4 stroke,get a manual to help you out.the honda is fairly simple with the uni cam but if you dont know what your doing...