forged 3-5/8" big bore piston kit. +.020"

Fits all 3-5/8" big bore 36-84 B.T. models with 4-1/4" to 5" stroke flywheels with the correct flywheel diameter of 8-1/2. Note that 4-3/4" & 5" strokes require 8-1/4 small diameter flywheels, all in combination with the appropriate cylinder length like mentioned below. Advanced alloy and piston skirt profile is used for low noise and long engine life. Piston dome volume 30cc, piston deck height 1.260".