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To rebore a Royal Enfield J2 1949
#790287 11/16/19 10:51 pm
Joined: Nov 2019
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Hello!! have a Royal Enfield J2 1949, I need to rebore Cylinder & Buy a new pistón, i have a doubt : How much is the clearence between pistón & cylinder when rebore in the grinding machine? Thanks

Last edited by Richard77; 11/16/19 10:53 pm.
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Re: To rebore a Royal Enfield J2 1949
Richard77 #790290 11/16/19 11:21 pm
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The diameter (and hence the clearance) depends on the piston's alloy. Thus, a new piston usually comes with the bore diameter required.
.. gREgg


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Re: To rebore a Royal Enfield J2 1949
Richard77 #790315 11/17/19 6:04 am
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Yes, you (or your machinist) needs the new piston in your hand BEFORE doing any reboring.

Clearance would typically be 4 or 5 thou, but the instructions for the new piston will say exactly how much.
Its a bad mistake to bore it with less than instructed, in the belief it will give it magic properties....


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