Originally Posted by
1200SportsterRider
Maybe some unhandy guy tried to lower the compression ratio. I could make it neat on my lathe.
And that would lower the compression ratio
(Depending on how thick the band is)
Your unhandy guy could have more easily ground off or filed down the piston hump. A shim under the cylinder made from aluminum pie plate would do as well and easily removed later.
Be very careful about holding pistons in three or four jaw, hard jaw chucks.
All too easy to distort the skirts.
Better to use an
exact, on-size colllet or custom bored, on-sized aluminum jaws, lightly clamped to avoid the hard, pressure points. At very least , a six jaw chuck would be less risky than a three.