Sorry if this topic has been done to death but its my first time attempting a re bore!
Have just got my self a new set of JCC pistons and Hastings rings +040 ready for a rebore, on my 65 thunderbolt rocket.
the old pistons were +020 and blowing a good amount of smoke from both cylinders under load, esp.. the rhs, this was due to corrosion marks low down on both bores, as this bike sat for a long time in the states before it was resurrected, also some scoring on both pistons that looks like it might have gotten a bit warm at some stage,valves & guides are good, no play evident no evidence on back of valves of oil! and only 1000 miles since I o/hauled the head.
My question is what would be a safe piston/ bore clearance for the JCC +040 set up also ring gaps, new pistons measure 2.988 at bottom of skirt 90 deg from pin and 2.983 under the oil ring groove
I ride the bike mostly on short trips and the odd long haul at no more than 65mph so its never under any major duress so fingers crossed this re bore will give me many happy miles