946481 Replacement 80" Flathead piston kit. +.010"

For those working on the rare and powerful 80-cubic inch Big Twin Flatheads, this MCS piston kit is a vital find. These cast aluminum pistons are designed for 1937 to 1941 1300cc Side Valve engines with a 3-7/16 inch bore. This particular kit is a .010 inch oversize, ideal for refreshing a cylinder that needs a light bore to restore a perfect seal. Sold as a set, the kit includes pistons, wrist pins, retainers, and rings, serving as a direct replacement for OEM 22218-30. As with any high-displacement vintage rebuild, it is critical that a skilled mechanic checks all clearances and that the rider follows a strict break-in protocol to ensure the longevity of these 1300cc components.