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Can 200 be bored to 250?

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Can a Rev 3 200 cylinder be bored to accept the 250 piston? Is it the same casting with the same ports/ port timing?

Even if it is you'd have to have the cylinder re-plated and properly size rings and piston. My guess is since they have different crankshafts the stroke is different the ports don't match. So now you'd be replacing the crankshaft as well. In the long run you could easily spend more money trying to make a 200 into a 250 then just buying a 250.

Summary:

No don't even try unless you own a machine shop and have a lot of time and money to spend.

I believe the 200 beta is a 250 sleeved down if it is possible to remove the sleeve you would probably have to have the barrel chromed easier to buy 250 (or 270) top end though not cheap!

Early ones apparently were sleeved down 250s (I was told I could get an oversize piston) but 03 or so onwards are plated alloy.

  • Author

Are the crankshafts really different? The specs I found are that the stroke is the same for 250 and 200 so what is different about the cranks? It looks like Beta took a different approach than Gas Gas by sleeving down a 250 rather than boring out a 125. Although mine is a 2008 so probably does not have an actual sleeve like mentioned in the post above.

Dan

If the stroke is the same I withdraw my conclusion. I thought it might be because the parts lists I looked at have different numbers for the crank.

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