For GY6 150cc 57.4mm Big Bore Kit Set Cylinder Head Piston Gasket Set QMJ157

GY6 150cc Big Bore Kit Set with Cylinder Head

This 57.4mm big bore kit set includes the cylinder, cylinder head, piston, and gasket set needed to rebuild a GY6 150cc engine, adding displacement for stronger mid-range output.

Overview

This GY6 150cc big bore kit set is a top-end rebuild package for scooters and buggies running the QMJ157 engine family. The 57.4mm big bore kit set raises displacement over the stock cylinder while the included head, piston, and gaskets let you complete the job in one pass. It suits riders and small-engine mechanics rebuilding a worn or underpowered 150cc top end.

Built For Performance

• 57.4mm cylinder bore that increases displacement over the stock 150cc cylinder
• Cylinder head matched to the GY6 150cc top end
• Piston and ring set sized for the 57.4mm bore
• Complete gasket set for sealing the cylinder, head, and covers
• Aluminum cylinder construction for heat dissipation under load
• Kit format that covers the main wear parts in a single order

Fits These Machines

• for GY6 150cc scooters using the QMJ157 engine
• for 150cc buggies using the QMJ157 engine
• for 150cc ATV models using the GY6 engine family
• for QMJ157 based go-karts

On-The-Job Use

• Top-end rebuilds on high-mileage 150cc scooters
• Restoring compression on a smoking or hard-starting engine
• Buggies and karts run hard on trails and dirt tracks
• Daily rider scooters that need dependable mid-range power

Specs At A Glance

Good To Know

Q: Does this big bore kit set need any machine work to install? A: The cylinder comes ready to bolt on, but checking piston-to-wall clearance and ring end gap before assembly is good practice on any rebuild. Q: Can I run the stock carburetor with the GY6 150cc big bore kit set? A: The engine will start and run, but a rejet or larger carb is often needed to get full benefit from the added displacement.

Slight variation in finish or dimensions may occur between production runs, and fit can depend on serial number, so confirm compatibility before ordering.