The NCY 61mm Big Bore Cylinder Kit is a high-performance 171.3cc bolt-on upgrade designed to significantly boost the power and torque of Genuine Buddy 150/170i scooters and 125/150cc GY6-based bikes. Constructed from lightweight aluminum for superior heat dissipation, this kit is the only 61mm cylinder available in the U.S. that features a smaller outer skirt diameter (62.99mm), allowing for installation without cutting or machining the engine cases.

Notice: This product is intended for off-road or racing use only and is not legal for use on public roads or pollution-controlled vehicles in California.

Features & Benefits:

• Bolt-On Performance: No engine case modifications required due to the slim 62.99mm cylinder skirt.
• Superior Cooling: Aluminum construction ensures the engine stays cooler under high-stress conditions compared to cast iron.
• Lightweight Piston: Includes a high-performance, cut-down piston to reduce reciprocating mass and increase RPM response.

Technical Specifications:

• Displacement: 171.3cc
• Bore Size: 61mm
• Outer Skirt Diameter: 62.99mm
• Material: Aluminum
• Included: Cylinder, Piston, Rings, Wrist Pin, Clips, Base Gasket, and Head Gasket.

Detailed Model Fitment:

This kit is compatible with most 125cc and 150cc 4-stroke engines (GY6/QMI152/QMJ157) and specific Genuine Scooter Co. models:

Genuine Scooter Co.

• Buddy: 150, 150 Anniversary, 170i
• Hooligan: 170i
• Blur: 150

GY6 / Chinese Import Models (150cc):

• TaoTao: Powermax 150, Lancer 150, Quantum 150, VIP 150
• Wolf Brand: Lucky 150, Jet II 150, EX-150, Blaze II 150
• Ice Bear: PMZ150 series, Mojo, Padere, Knight
• Peace Sports: TPGS-808, TPGS-840, B08, Roar 4
• BMS: Heritage 150, Chelsea 150, Grand Prix 150, Bemine
• ZNEN: Amstar, Eagle, Falcon 150, ZN150T series

Engine Code Compatibility:

Fits engines with the following stamps:

• 157QMJ / 1P57QMJ / JJ157QMJ / BN157QMJ
• 152QMI / 1P52QMI
• 161QMK / 1P61QMK / BN161QMK-A

Don't see your engine listed? If the engine code includes "QM" or "FM" this part is compatible with your vehicle.

Pro Tip: 

• We recommend jetting this kit significantly richer due to its high-performance capabilities. To optimize both performance and efficiency, consider upgrading to our 61mm big valve head, as some stock heads may not be compatible.
• Have a look at our Decompression Tube Assembly, which replaces your dipstick and allows excess crankcase pressure to be released. It’s a good idea to install one of these alongside any cylinder kit upgrade.

Visit our NCY Performance Parts page to shop all performance upgrades available for your vehicle.

About NCY: NCY is the aftermarket performance parts leader for the most popular scooter brands, including Honda, Yamaha, Genuine, Vespa, SYM, Lance, KYMCO, and GY6 / QMB powered scooters. Made in Taiwan with strict quality standards since 1997, NCY is ISO 9001 certified.

Made in Taiwan.

This product is intended for off-road use only.

This product is not intended for use on public roads or land.

This product is not legal for use in California on pollution-controlled vehicles. Check local laws before installing.

*Performance upgrades are considered racing parts and are not covered by warranty.