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crf250 chassis with crf450 engine

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im sorry.. i dont understand the logic in this?? i mean the chassis is just about the same between the 250f and 450 except for some changes of couse.. but really whats the poin in spending thousnds exstras in work? when you could just buy the 450?

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By accident I dropped an 01 YZ250 motor in my 04 CRF250. :banana:The original 250F motor was toast and I had a CR500 in it that broke the second ride. Got the carb dialed in today and it pulled like a modded 250 smoker should. Hope to take it out this weekend for a real test.

Craigus

stroke2.jpg

stroke3.jpg

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hey there cryzrider.i can imagine your bike handles very well.i was on a 250 yz and it was very lively.lovely throttle response.i've had an 03 crf450 for about 2 years.i love the engine but it was a bit clumsy and heavy.honda over engineered the early 4 strokes.i bought the 250crf frame, subframe, fuel tank, airbox and plastics.the front and rear of the 450 went straight on to the 250 chassis.the frame was'nt hard to modify.just move the bottom mounts, make up a new front mount and refrabricate the area above the carb.the fuel tank needed modifyiny too but it was easy to do.it was all professionally welded.the cost of the all the 250 bits and fabrication was the equillavent about 800 dollars.i live in northern ireland.the bike handles real nice.you can notice the difference.it's easier to ride.

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Hi SiJodee,

I appreciate this took place a few years ago and despite the haters I'm intrigued about any issues you encountered.

I've done both a 500af and 250af using the 05 subframe but 06 250f Chassis. Clearly a lot of fabwork on both builds. I don't want to be going to that extent again but my 450 is the only bike not in the same chassis and for the sake of motor mounts I'd be ok.

What were the issues with the Carb? Can you still use the same boot?!? The fuel tank I'm ok with doing. The upper motor mount how was that dealt with? Exhaust mounts and routing? Any dramas with the radiator plumbing? Finally, where did you mount the coil? Or did you use the 250 coil plug cap.

Hope that's not too much and nice build bud.

Cheers,

Rob

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