Boring out the jug?

1 reply to this topic
  • fitzpcj01

Posted January 10, 2014 - 02:30 PM


02 yz426 curious what all I have to change to bore it out. I know the piston rings blah blah but what about the cams, or crank?

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  • grayracer513

Posted January 10, 2014 - 04:50 PM


 If you are repairing a wear condition, you cannot bore the cylinder.  There are no oversized pistons, all of them are standard.  The cylinders are Nikasil plated aluminum, and must either simply be replaced, or honed oversize and replated, then honed back to size.


If you want to oversize the engine, there are big bore kits you can buy that include the piston, rings, and cylinder, along with the necessary gaskets.  It is not necessary to do anything with cams or the crank that isn't mandated by some kind of wear condition.

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