UL clearance

[kg993]

I am boring a badly pitted set of UL cylinders to 3 7/16 std. Can someone tell me the piston to bore clearance. Don't have a book on B.T. Flat Heads.
Thanks, Kerry Glaze

[Rubone]

Kerry,
That purely depends on what pistons you are using. Factory Harley is .001-.0015. Most aftermarket are in the .003-.004 range. Who made them and are they cast, forged , etc, as it is all different! Max wear allowance is about .006 over that clearance.
Robbie

[kg993]

They are from V-Twin, cast pistons.