KB266040 Performance, 1340cc Evo B.T. pop-up piston kit. +.040"

This KB Performance 1340cc Evo Big Twin pop-up piston kit is designed for high-performance builds requiring a 10.5:1 compression ratio. Sold as a set in a +.040" oversize, these pistons feature a 0.200" dome to significantly increase power. Constructed from T6 heat-treated 390 hypereutectic aluminum with 16% silicone, they offer superior strength and the ability to run tight clearances for a quiet-running engine. These fit 1984 to 1999 1340cc Evolution Big Twin models. Because of the high-performance design, the top compression ring needs specific additional clearance, so make sure to follow the technical instructions closely during your top-end assembly to avoid any ring-binding issues.