hey guys i have been kicking around the idea of a 10.25:1 piston, a web cam probably the 180 grind number
valve lift .350/.350
duration 252°/252°
duration @ .050. 228°/228°

or the powroll cam (doesn't have specs) what cam would you use?

i will probably do mild port work and i was thinking of the 40mm mikuni hsr carb i would like to get your guys opinion on the carb also.

i know its hard to say but it would be nice to have in opinion on the hp numbers.

 

The powroll cam spec are midrange grind 355 /360 and the race grind cam is 360 / 360 . Everyone I have talked to says the web cam is the best .
I am collecting parts to rebuild my bike . I have a 82m wiseco 10.25 to 1 piston , powroll midrange cam /rocker arms and a ported head , I need a set of valve springs and a new triming chain . I am waiting until I have all the parts to rebuild it before I tear it down . The engine is stock and still runs good but I plan to rebuild it this winter . I am going with a 400ex carb . I think a 40mm would be too big . Maybe go with a carb from a 230 crf the earlier bikes had a 37mm carb and then they went to a 40mm I think around 2005 or 2006 Hope this helps

 

thanks man helps alot. how much of a difference does the piston, and porting make? are you running the 230 carb?

 

thanks man helped alot. how much of a difference did the piston and porting make? and are you running the 230 carb?

 

I just have the parts to build mine I still need to rebuild it . My son has a 350x engine that has a .20 over wiseco 10.25 to 1 piston ,ported head and a 400ex carb and his bike screams . We didnt have the money for a cam when we rebuilt it because its not just the price of the cam ($200 ) its the hardened rocker arms ($65 each x 2 ) and the stiffer valve springs ($130) . The 400ex should do fine for what you want . The crf230 carb will have better throttle response but they are expensive , around $200 to $250 . To give you an idea how big a difference the piston makes a stock 350x has a 8.5 to 1 compreesion ratio just jumping up to a 10.25 to 1 piston makes a big difference . Both my son and me have a 350x engine in a 300ex frame . When we drag race we stay together until about 3rd gear then he pulls away by a couple of bike lengths . I dont think its the higher compression piston as much as the porting and the bigger carb . If you are on a budget like me look on ebay for 350x parts . I got my piston for $60 and I got the cam from ebay also from a guy who built his motor and didnt replace the timing chain and fried his head . The cam was only a month old and I got it for $75 . I was leaning towards the webb racing cam but couldnt pass up a powroll cam for $75 . I need a few more parts for my engine but until then it still runs great and doesnt smoke so I am going to run it until I find the rest of my parts .