Vintage Dirt Bike Q & A

Any help would be appreciated. My CR250 has always run well. It gets rebuilt every winter and lasts the whole year. However, right now I have a problem. The bike hits about 4,000 rpm (this is a guess) and acts like it has hit a rev limiter. Under 4,000 it runs perfect. It doesn't foul a plug or anything, just won't wrap any further. I have changed the plug, the stator and the coil. I also unplugged the kill switch. Nothing seems to work. Jetting is stock and the same as it always has been. The only thing I haven't tried is to replace the CDI - their expensive but I'll do it if likely the problem.

Thanks in advance for any help.

Clint

Does it run good right up until it starts running bad? Is it idling okay, pulling smoothly from down low until it starts... until it starts what? Is it just stock at one constant speed or is it breaking up?

There are several things that can cause it to not rev including high speed stator being one of them (you say you replaced it), a fuel or exhaust problem not allowing enough fuel in or enough exhaust out... the core isn't broken in the silencer is it? What about fuel flow is it flowing well into the carb?

What about the reeds - if they are broken it will crank (idle bad to horribly) and then as it revs higher and higher it'll get worse and worse!

Sounds silly but have you checked your jets? I've ridden bikes I could get cranked and going and then they'd break up like mad - told the guy to pull his float bowl and sure enough his mainjet was laying in the bottom...

Check fuel flow and exhaust obstructions first.

No rag in the air filter right? *wink* just kidding that's an old joke.

Peace...
Mikeee P

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The Race Isn't Over Until YOU Cross The Finish Line!

Thanks for the response.

The bike runs and idles perfectly until the higher rpm. I haven't checked the reeds, which I will tonight, but fuel flow and any obstructions seem fine. The jets are in place and clean.

I'll check the reeds and see what I get.

Clint

check you fuel delivery system really good. replace fuel line in case of air leak.

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Terry Moody #48f
3x 74 Honda CR250M Elsinore
74 Honda XR75
73 Honda QA50
78 Yamaha YZ125E
78 Yamaha YZ250E
78 Yamaha YZ400E
79 Kawasaki KX250
79 Honda CR250R
79 Suzuki RM400
80 Honda CR125
2x 83 Honda CR480R
98 Kawasaki KX250

Will do.

thanks..