GY6 161QMK Engines 67mm Cylinder Kit 4 Valve

67mm Cylinder Kit for GY6-B/GY7/161QMK Engines

This 67mm 4 Valve Cylinder Kit suits GY6-B, GY7, and 161QMK engines, raising displacement to 232cc when used with a matching stroker crank. It comes with a ceramic-coated cylinder and a forged piston, so it appeals to riders looking for a dependable performance option. Within our GY6 scooter parts range, this kit is built for four-valve engines, which helps it fit correctly and deliver better output.

Cylinder Construction

The cylinder is coated in ceramic, which helps it shed heat and cut down on friction for smoother efficiency. The forged piston supplied with the kit weighs less and is tougher than standard cast pistons, which makes it a good match for demanding builds. Every part needed for installation is included, so you have everything for a complete upgrade.

Installation and Compatibility

This kit is made for B-case GY6 4-stroke engines with 57mm stud spacing. It works with four-valve setups and can be fitted without extra modifications. If you want more power and efficiency from your engine, replacing the cylinder is the recommended step.

Specifications

• Cylinder Bore: 67mm
• Cylinder Height: 76mm
• Overall Height: 103.5mm
• Stud Spacing: 57mm (B-case)
• Wrist Pin Diameter: 15mm
• Compatible Engine: GY6 QMI/QMJ 152/157 (B-case long case)
• Max Displacement: 232cc (with 66mm stroker crank)
• Fits: GY6 B-case / GY7 161QMK builds with 57mm stud spacing and a matching four-valve Cygnus-style head

Fitment

Fits:

• GY6 QMI152/QMJ157 engines (B-case long case, 57mm stud spacing, four-valve head required)
• GY6-B / GY7 / 161QMK four-stroke builds (B-case, 57mm stud spacing)

How to choose: Confirm your crankcase has 57mm cylinder-stud spacing and a B-case long case, and pair this kit with a four-valve Cygnus-style head.

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