S&S Cycle SS910-0688 1200cc Big Bore Kit Silver for Sportster 86-21 w/883cc EngineBoost any 883cc Harley Davidson Sportster to 1200cc. No machine shop? No problem, no machining is needed. Dont want to rebalance your stock 883cc flywheels? You dont need to since these pistons weigh the same as stock 883 pistons. Cylinder head modification is also not needed. The dished piston dome keeps compression down to a streetable 9. 4: 1 with stock 883cc heads. Installing this kit takes the same time as replacing a stock top end. Its just more