Does anyone know if Big Bore kits come with the rings already gapped or is that done at the time of assembly?

 

Depends on who you buy the stuff from. Places like Hillside will fit the rings to the cylinders. If that's the case, the rings will be on the pistons, and they will be marked. The corresponding cylinder will have the same mark. If you buy a kit and the rings aren't already on the pistons, but are still in the box, you'll need to gap them yourself.

 

As Cuda said, and as an unsolicited general rule, "Never install new rings without checking the gap." period. It just isn't worth it. I .001" difference in bore is .003" difference in ring gap so it's real easy to get in trouble. For the price of a set of feeler guages and a little time, you'll sleep better and avoid some scored cylinders if the gap is non-existant in actual use.

 

After hundreds of bb installations I never seen rings from a HD kit needing any further attention but we check them every single time just 4 conformation. After market I've no experience but a couple of Dave Mackey kits & they were set correctly out of the box as well. I'd check everything anyway just so you know its correct have fun & #ridesafe

 

Mine were CP pistons, and yes the rings needed gapping. I bought one of those rotary gapping tools for around $40.00 and it did the trick no problem.