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49cc or 70cc?

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Just bought a used 97 xr 70. On the motor it's stamped 49cc.

Does it come this way from factory,but actually has 70cc bore and stroke?

Or has someone replaced the motor with an actual 50cc?

Also does any one know what size carb comes stock on a 70?

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If it came from the factory, it would say 72 cm3, somoeone has replaced the cylinder on it. You will have to remove the cylinder head, and measure the diameter of the cylinder bore to determine what displacement it is. DRATV makes aftermarket big bore kits from 50 to 85cc with the cylinder marked 49cc.

39cc diameter = 50cc engine

47cc diameter = 70cc engine

48cc diameter = 75cc engine

51cc diameter = 85cc engine

Someone may have freshened up the engine with another 70cc kit, or possibly just stuck a stock 50cc top end on it, to make a running engine.

I think the stock carb for an XR70 is a 17mm.

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