KB920C040 1340 Evo B.T. forged piston kit. +.040"

Refresh your 1984 to 1999 1340cc Evolution Big Twin with this high-strength KB Performance forged piston kit. These +.040" oversize pistons are forged from 4032 aluminum alloy, providing the structural integrity needed to resist cracking and handle high-performance demands. Sold as a set, they feature a domed head design that yields a 9.5:1 compression ratio with stock 80cc heads. The kit includes wrist pins, rings, and retaining clips. Because these are forged, they require a slightly wider piston-to-wall clearance of about .001" compared to cast alternatives. The offset wrist pin design ensures a quieter engine, but requires careful attention to the front and rear installation instructions. This kit is a reliable way to restore power and durability to your classic Evo motor.