XC motor build

[badtothebone250]

Hey guys now that I'm back on a 250r I am more than excited to turn my woods weapon into a 450 killer. Honestly I do think that I have plenty of room to improve my skill but at the same time I want to have a machine that has the capability of taking down the 450's in the B class or higher. I have no problem in the c class so far. I have a spare 88 motor that is stock other than a cr head gasket. My thoughts are to build a motor that would be in a "factory honda" if the 250r was still the race quad of choice today. My inspiration came from a guy on allthingsmoto.com that built a 2001 CR250 motor for a hybrid bike he was building. Plans for the motor include starting with bare engine cases, all new bearings, cryo treating every moving part in the bottom end (not sure about crankshaft yet), having the crank/piston assembly professionally balanced, having a reputable engine builder port the stock cylinder, and anything else that comes to mind. I am not looking for a fire breathing motor that is going to wear me out in a race. I prefer a smooth motor with a broad power band, yet plenty of juice to get down in the open sections. I am open to suggestions and hope to get this little project started soon. It will be a slow build process because I want to make sure everything is done correctly and I will have no disappointments! Let me know what suggestions you may have!

[rockingkfarms]

Call Arlan at LED. I have a variety of 250R top ends. He makes the best XC motors of anybody I've tried. Not cheap but worth it...

[troybilt]

Awesome idea! I like woods motors myself. I would also suggest B&B for porting your stock cylinder, B&B ported Tony Kelner's motors for Barry Hawk, I had one and had it tractor like torque, it was amazing!! Arlen is great too, like already mentioned. LED builds Matt Smiley's motors, but they are 300PV's not stock cylinders.

I would also go with a Boyesen Rad valve with the RL19 reeds for woods.

35 A/S carb or 36...

As far as pipe, I'd look for a Paul Turner Type 6, ESR TRX7, LRD adjustable,

Just some suggestions!

[tbone250r]

I'm lookin to build an XC motor as well.

I picked up a PC2000 275PV cylinder the other day and i'm gonna try that out for the time being.

I was thinking a Sphinx 300cc +4 stroker would be a deadly woods machine.

[badtothebone250]

Thanks for the suggestions guys! Already have a paul turner type 6 pipe and 36mm carb. The bike currently has a v force reed cage but if it is worth the extra cost to switch it out to a rad valve I will. The bike already has pretty smooth power and decent low end with the pipe, I just have a hard time running down the 450's in the open sections and on the starts. I am a little weary of aftermarket big bore cylinders because I don't want to sacrifice any reliability at all. I will do some research with the builders you guys mentioned! Thanks!

[rockingkfarms]

Your Type 6 pipe was the best true XC pipe ever made.
Do not be afraid to run a big bore cylinder. A powervalve is the way to go for woods. I would stay in the 300 range. Too much hp will just wear you out in the tight stuff.

[89trx250r]

If you do use Arlan just be prepared to open your wallet and then hand it to him and walk away lol...

[badtothebone250]

Is Arlan that much more expensive for just port work?

[tbone250r]

Ya I would really like to know Arlen's pricing in comparison to others.

I love that he posts a ton of videos on stuff in the shop. He has a bunch of videos of him porting CPI Sphinx 300 cylinders.

Just really cool to see the work actually being done. Instead of being ultra secretive