[thunderrock71]

I am sure this has been asked before, but i cant find a post that says "these things combined together will give you bottom to mid power with 60 horse and 43 Ft-lb's killer CRF450X. Thats what im looking for.
I am looking for a Worcs race bike based on a 2005 CRF450X with a airbox, smog removal, silencer, and pink wire mods already done, just need more POWER. My brothers all race the 450B/C class and i am looking to beat them. They have a 2015 Dungey Replica, 2014 KTM 450, 2010 Yamaha 450, and new Suzuki 450. All have miscellaneous modifications, I am just looking for a proven motor setup, head, piston, pipe, with atleast 55+ HP and 40+ ft-lbs. I would consider a big bore but it would not be my first choice.

Thanks for the help.

[JimDirt]

Welcome to the site !!

I voted (High Compression), but just wanted to say , the higher compression piston will give you a lot of bottom end punch , a HotCams Stage 1 will also , but you will fall off on top end , which you might need for WORCS racing , so maybe a Stage 2 cam OR a 02 or 07 or 08 R cam , will help getting the power where you want it (PM Ken , he can guide you on where each cam works best , his user name is crfsonly ) , i also used TRX intake size valves in mine , they are 1mm larger than the stock X intake size (obviously you have to have the seats cut larger) , it seemed to help the engine breath better (I used Ferrea 1mm larger Stainless intakes) , the actual mods done will depend on the way you ride the bike , if you rev it , you will want to keep your power in Mid to Top end , if you ride a gear high , then you will want to direct the useful power more to the bottom end , and mid range of the RPM range

[thunderrock71]

Thanks for the response, I tried changing the pole questions after putting them up but it won’t let me edit the questions now. After thinking about it I thought a head, cam, valves, HC piston 13.5-1?, and or maybe a vortex or 450R CDI might give me what I am looking for? As far as mid low VS top end power, I ride a gear high as much as possible since the bike seems to like pulling thru the gear instead of revving its brains out. We have been practicing on sand tracks a lot while trying to maintain momentum and leaving the bike in 3rd, upshifting when needed seems to work best. So I think I want Low to Mid power increase but not losing top end.

I will PM crfsonly and see what if he has a proven combo. I just want to ride when I get the chance I’m over wrenching, it’s the whole reason I quit snowmobiling. Thanks again

[JimDirt]

No problem , and once you get it set , then you should be good , about the worst you will have to worry about is racing different elevations , and getting the jetting adjusted for each elevation change

[Leardriver]

I always hear that all the power is in the head.
A ported head, slightly higher compression JE piston, and an R or stage 2 cam will give you all of the bike that a mere mortal can hang on to for an entire race.