Vintage Dirt Bike Q & A

I recently bought a 1977 cr 125. The crank is locked and i am unable to split it. Tried finding a used replacement. What i would like too know is how much modification would be required too replace the 125 cr motor with a 1977 250 cr motor. If anybody knows or has tried this please let me know. Any help at all would be appreciated.

Have you considered having the crank rebuilt? Racers Toy Store in Escondido, CA will do this for you, as will Arizona Crank Works...

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Michael Stiles
1979 Honda CR250R Elsinore | 2006 Husqvarna SM510R | 2007 Service Honda CR500R-AF

the 125 cr motor on it is shot i know where i can get a 250 motor for dirt cheap that runs it's a 250 cr or mt. what i need too know is how much work will it be too fit the 250 motor on a 125 frame.

Why not look for XR motor and make a 4-stroke hybrid. It may be easier and safer.

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#829 The "Factory Novice"

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