The KB PERFORMANCE Forged Piston Kit is engineered for street‑oriented 80‑inch Evolution Big Twin engines, delivering a precise bore of 3.498 in with a +0.030 in oversize. Constructed from a hypereutectic alloy, the pistons provide the thermal stability and wear resistance needed for the 1340 cc displacement while maintaining an 8.6:1 compression ratio. The kit’s dimensions and material selection are optimized to support reliable power delivery and consistent performance under everyday riding conditions.
Delivered as a complete piston kit, the package is ready for installation on engines built to the 80‑inch specification. In addition to the standard +0.030 in, 8.6:1 configuration, the line also offers a +0.040 in, 9.6:1 option for riders seeking a higher compression setup, ensuring the kit can be matched to the desired performance envelope without compromising the engine’s original design parameters.