CRF Engine mod advice needed

[Hbmtr]

Hi all. so i am sledless now that i sold my 09 dragon but got a 07 crf 450,that i have pulled the moter ,tore it down the the cases.My plan is to build a nice reliable but sweet engine using high quality after market rod and piston,
I am working with LED performance in Gresham Ore.
Since i have yet to ride a snowbike yet have put many miles desert racing and years off-road riding. My question to u is this,should i build for more bottom end and mid range or mid to upper rpm range?
I know i am going to have a blast on this thing but want to build it right for the snowbike application.I have other bikes i ride for the desert.

 

[slash]

Web Cams Inc make some good torque cams that work bottom to top

 

[Hbmtr]

I am going to run the stock r cam.I am going to use a carrilo rod and cp piston.

guess my question is should i go with a lighter crank or a heavier one for more inertia?

 

[evberger22]

When I built my motor a few years ago we sent my stock honda crank down to Falicon and they rebuilt it with one of their knife rod setups.Might be a tad lighter than a stock crank but not much,just balanced to perfection. Ran a full supermoto season on that crank then pulled motor apart to check it and everything looked good still.My first season was on a bone stock motor and everything looked good also,nothing wrong with a stock honda crank either. Stuck a new CP piston in (JE is just as good I've ran both). Works wicked good as a snow bike motor. Also has port and polish, web cam, factory pro jet kit, upgraded ignition, lightened flywheel,fresh valve seat grind with stock valves ,ferrara springs and retainers with full akropovic exhast. Dynoed about 10 more rwhp than stock 450 on a mustang dyno. To scary to ride as a mx bike in the dirt.

 

[evberger22]

Same motor as you 07 CRF450R. Also just installed raptor t-stat to make some more heat. And just installed snorkel style intake, I gave up on trying to seal up stock airbox. I'll get some pics next time.

 

[Hbmtr]

evberger that was the exact info i was looking for.At this point my head is getting ported and polished,new oem valves intake ,exh,and oem springs.Yhe seats are getting recut,and set up with proper spring pressure.
I like the idea of the Falicon knife crank,but probaly out of my price range.
My crank is going to Crank Works in AZ for the Carrilo rod install and balanced with the cp piston and pin.
The one other thing is i am going with a custom sleave for the cylinder to make overall displacement a 488.
Can you tell me more about what ign.set up you are using? { Vortex } ?
So do you rec. any extra weight to be added to the crank or take some off?

 

[evberger22]

The 488 kit might not rev as fast as a 450 but it will have a little more grunt and torque. As for the crank weight my mechanic always just left it stock, they seem to work just fine that way. We did however take some weight off the flywheel stater cover to help the bike rev a tiny bit faster. As for the cdi I am running an old Procom that my mechanic had sitting around that he ran on his 05. I did feel on the supermoto track that it did help, almost felt like it hit a little harder down low. My Procome is not adjustable but the vortex is. My mechanic ran the vortex and did some dyno time with it .Same idea as procom but you can move the hit around a little bit, or set it to what you feel suits your riding style. The best thing I felt that gave me more instant throttle response and quicker boost down low was after we installed the factory pro emulsion tube, needle and dyno tuned it. Really woke up the fcr carb and came down a bunch of main jet sizes.

 

[Hbmtr]

thankyou for your info