CR 250r Bottom end power!!!

[cr250enduro]

I have a 1990 CR 250 that i would like to use for enduros and hare scrambles. It is stock right now with the exception of a 120z flywheel weight and a set of steel Moose clutch plates and springs. I am planning on getting an FMF gnarly pipe and FMF silencerwith spark arrester. What other mods can i do to give the bike some more tractable power down low. I have mostly ridden four stroke dirtbikes and i am still not used to this bikes power...especially in the woods lol....any help would be greatly appreciated

 

[Rcannon]

Have you actually tried the bike yet? I have my YZ 250 set up similar to your bike . I also came off of a 4 stroke.

No, my bike does not have the extreme low end torque of my DR 350, but it has enough. I think your Honda has more low end than my bike to begin with. The flywheel weight is the coolest product I have ever used on my machine. I cannot say it added low end, but the bike does not die at low rpm's. and will crawl its way up anything I can find. It runs well enough to follow my nephew around on his xr 50.

 

[dbrace]

You could maybe try some carbon tech low to mid reeds. I also would use a std length silencer as those shorty style ones take away bottom and give a mid-range hit.

 

[Lissa]

cr250enduro, are you planning to compete in the ECEA series? I compete in the ECEA Enduro circuit. I did own a '00 CR250 and did a few minor mods to increase what bottom-end hit it had. A flywheel weight does not add bottom-end power, it just helps with stalling at low RPM's and smooths out the power delivery. First thing, though, I would have your suspension dialed in and/or revalved for off-road use. Stock valving and springs will most likely pogo you until your hammered. For the motor, resin reeds are good for promoting more torque, like Boyeson's Torque reeds. If the final gearing is stock, add a two tooth larger back sprocket to bring the hit lower in the gears. For off-road legality, purchase a FMF Q' series/ spark arrestor of some sort. If you have a few extra bucks to spend, purchase a FMF Fatty or Gnarly pipe. You'll also want to get a pipe guard. Make sure your machine is jetted properly and that your top-end (piston+rings) is fresh before you start competing. A worn top-end is a great loss of performance. Besides, some ECEA enduros or Hare Scrambles will extremly tax your motor and the rest of the bike, so make sure its a 100% before you get to the starting line. Sometimes it could be a very, very long push out of the woods. Make sure all of your wheel, shock, linkage, and steering head bearings are tight, too. Water proof your bike by routing two carb vent hose into the airbox to prevent bogging in a mudhole. Also check your airbox to make sure its seams are tight. See you at the Enduro's.

 

[dancrosbie]

Actually the shorty silencers give you more bottom and mid but are probably too loud for enduro anyways. My 0.02 cents.

 

[oldslodave]

Hey CR250R.. You can have your cylinder ported to move the power band down. I had this done to my 96 CR with great results. With an FMF torque pipe, it feels like an open bike off the bottom and through the early part of mid range. The down side is it falls on its face on top end, very little of that famous Honda over rev. It also was a handful in slippery conditions.
I was pretty much a beginner when I had that bike and have since learned that all 2 strokes have plenty of torque. It's just hidden in that lever on the left!! Seriously, my buddies explained (and it took a while to learn) that you nearly constantly slip the clutch a little bit to keep the motor rpm up. It's a delicate balance, because to much slipping will cause the motor to overheat. And on one particularly gnarly hill, I actually heard the oil in the clutch bubbling when I shut the bike off at the top. But after a while I got the hang of it, and it works great. Ask some of your 2 stroke "A" rider buddies or anyone that raced a 125 successfully. Good luck.

 

[Dirt Guy]

I had a 90 CR250 and had good results with the following setup: Moose steel clutch plates, (I never tried a flywheel weight since I spent a lot of time on the track as well as the trail), FMF Torque pipe & Turbine Core spark arrestor, Boysen 2stage reeds, milled sparkplug seat in head for proper electrode protrusion into combustion chamber, cleaned up casting flash in ports. Fine tune all of this with jetting/gearing to suit your style.

I have had a couple of bikes since I sold this 90 and have been trying to get the feel of that motor back since selling it. It had good power throughout the power band and I think (pure opinion here) the combo described beefed up the bottom enough to make a smoother transition from low to mid. It still hit, but not as hard as when stock which was much better for my novice skill level.

Get your hands on one of Eric Gore's books, it was my bible for tuning that bike and his suggestions were right on, they worked well for me.