crf250 cdi on a crf450?

[Glamis400ex]

Anyone ever heard of putting a crf250 cdi on a crf450? Another forum boasts of a better torque curve and power delivery.

[stocktires]

Yes, but I've heard both ends of it.
Most well known motor builders completely disagree with it.
The CRF250 CDI actually makes the bikes slower, therefore getting more traction and FEELING faster. I've seen alot of motor builders do dyno runs on it to prove it.
Same way with using flywheel weights, they make the motor rev slower but you then gain more traction.
This is all in a bike chassis though, because the 4" rear tire with half the weight of a quad holding it down has a much harder time hooking up. So in a quad chassis, you would just go slower because traction is not as much of an issue. Also, I believe the CRF250 rev limiter is much higher, which makes it FEEL faster (VERY bad on a CRF motor). Some slower guys on bikes have made faster lap times with flywheel weights or CRF250 CDI's.

I would stay far away from it. If you have a later model motor (02-04), try putting an 06' CDI on it, that's what I'm planning on (dyno proven for maybe 1hp).


*I have tried none of this personally, this is all just info from forum and motor builder reads*

[Glamis400ex]

excellent explanation...makes perfect sense.