NCY 61mm 171cc No-Cut Big Bore Kit - GY6

Build more displacement into a compatible GY6 125cc or 150cc four-stroke engine with the NCY 61mm aluminum cylinder kit. The 61mm bore produces approximately 171.3cc with the applicable crankshaft stroke, while the 62.99mm outer cylinder skirt is designed for compatible engine cases that accept this diameter without machining. The kit includes the cylinder, piston, rings, wrist pin, clips, and gaskets. 

Key Features

• 61mm bore for approximately 171.3cc displacement on compatible GY6 engines
• 62.99mm outer cylinder skirt designed for compatible no-case-cut installations
• Aluminum cylinder construction for efficient heat transfer
• Short-skirt piston reduces reciprocating mass
• Includes cylinder, piston, rings, wrist pin, clips, and gaskets

Specifications

• Brand: NCY
• SKU: 1100-1288
• MPN: 603C02GY661
• Bore: 61mm
• Displacement: Approximately 171.3cc with the applicable stroke
• Outer cylinder skirt diameter: 62.99mm
• Cylinder stud spacing: 54mm (GY6-A block)
• Cylinder material: Aluminum
• Engine family: Compatible GY6 125cc–150cc four-stroke QMI and QMJ engines
• Excluded engine family: Does not fit GY6 B-Block,  or 161QMK engines
• Country of origin: Taiwan

Potential Engine and Model Fitment

Compatible 125cc–150cc engines marked with a listed QMI or QMJ code may use this kit, but verify a GY6-A engine case with 54mm cylinder stud spacing, the 61mm bore application, 62.99mm outer cylinder skirt, deck height, oil passages, and piston-to-valve clearance against the original engine. This kit does not fit 161QMK or other QMK engines.

Tuning and Installation

Increasing displacement requires fuel-system tuning. Carbureted applications generally require re-jetting, but the correct jet size depends on the carburetor, intake, exhaust, elevation, and other engine modifications. Professional assembly, clearance checks, break-in, and tuning are recommended.

This product is intended for off-road use only. This product is not intended for use on public roads or land.  Check applicable federal, state, and local laws before installation.

• 61mm bore produces approximately 171.3cc with the applicable crankshaft stroke
• 62.99mm outer cylinder skirt designed for compatible no-case-cut installations
• Aluminum cylinder construction supports efficient heat transfer
• Short-skirt piston reduces reciprocating mass
• Includes cylinder, piston, rings, wrist pin, clips, and gaskets

Brand: NCY | SKU: 1100-1288 | MPN: 603C02GY661 | Bore: 61mm | Displacement: Approx. 171.3cc with applicable stroke | Outer cylinder skirt: 62.99mm | Cylinder stud spacing: 54mm | Engine case: GY6-A block | Material: Aluminum | Engine family: Compatible GY6 125cc–150cc QMI/QMJ | Engine codes: 157QMJ, 1P57QMJ, 152QMI, BN157QMJ | Excludes: 161QMK and other QMK engines | Origin: Taiwan

Potential fitment for compatible GY6 125cc–150cc four-stroke QMI and QMJ engines, including 157QMJ, 1P57QMJ, 152QMI, and BN157QMJ. Does not fit 161QMK or other QMK engines. Verify the 61mm bore application, 62.99mm outer cylinder skirt, stud spacing, deck height, oil passages, and piston-to-valve clearance before ordering.