BRAND NEW Big Bore Kit GY6 Atv Scooter Engine Motor 50cc to 80cc. 4 Stroke. Includes 1x Cylinder Block. 1x Piston. 1x Complete Ring Set. 2x Cirq clips. 1x Piston Pin. 2x Head Gasket Set. Specs: Diameter: 47mm (53.2mm) Big Bore mostly fits: GY6 or GY6 engine clone (139qmb) Scooters. 50cc GY6 Go Kart engine. 50cc ATVs. 50cc Dune Buggies. 50cc Buggies. Fits many models suchas YERFDOG, SUNL, SYM, PGO, KYMCO, VENTO, STRADA, ROKETA, FUJI, WILDFIRE, KAZUMA