KB305020 Performance, 1340cc Evo B.T. pop-up piston kit. +.020"

This KB Performance 1340cc Evo Big Twin pop-up piston kit is designed to give your Evolution motor a performance boost. Sold as a set in a +.020" oversize, these pistons feature a pop-up dome design that increases the compression ratio to 9.5:1. Constructed from T6 heat-treated 390 hypereutectic aluminum with 16% silicone, they offer excellent thermal characteristics and allow for tight clearances to minimize engine noise. These fit 1984 to 1999 1340cc Evolution Big Twin models. During assembly, remember that the top compression ring requires additional clearance as specified in the instructions. This kit is a great way to add some extra power while maintaining the reliability of your Big Twin.