Complete 36mm GP290 big-bore kit. Now featuring improved cylinder plating for increased durability.

Includes 36mm cylinder, piston, piston ring, piston pin and two pin washers, circlips, cylinder gasket, two cylinder bolts, insulator gasket, and CMR7H spark plug.

Increases displacement to 28.5cc when used with a stock crankshaft with 28mm stroke. Increases engine power SUBSTANTIALLY - estimated power output is 3.5 HP! This high-performance product requires 91 octane (using the R+M/2 octane rating method) or higher fuel, and comes without warranty. This kit has the 38mm cylinder skirt and is compatible with 38mm cases.

Fits Zenoah G23LH / G230RC / G260RC engines. Also fits Chung Yang CY23RC / CY26RC / CY27RC engines. Also works as a complete replacement top-end for the "Version 1" GP290 engine with 38mm crankcase opening.