NCY Performance Cylinder

Want an easy, reliable way to turn your 150cc GY6 into a true performer? The NCY 61mm Big Bore Cylinder Kit bumps displacement to **171.3cc** — giving Genuine Buddy 150/170i scooters and GY6-based 125/150cc bikes a stronger pull everywhere in the rev range, without needing to cut or modify the engine cases.

The Details

NCY’s 61mm cylinder is the only drop-in big-bore kit of its size available in the U.S. (as far as we know). With a smaller outer cylinder skirt diameter of 62.99 mm — compared to the common 65 mm — it clears your engine cases with no machining required.

The kit also includes a precision lightweight piston designed to reduce rotating mass, helping the engine rev quicker and improve overall ride feel. Combined with performance upgrades like a big-valve head or free-flowing exhaust, you’ll get a noticeable bump in acceleration and torque where you actually ride everyday.

Specifications

• Designed for Genuine + GY6 125/150cc engines
• Outer Cylinder Skirt Diameter: 62.99 mm
• Bore Size: 61 mm
• Displacement: 171.3 cc (approx.)
• Piston, rings, wrist pin, and clips included
• Base gasket + head gasket included
• Does not include head assembly

Compatibility Overview

Compatible with Genuine scooters and most GY6-based 125/150cc engines with the following codes:

157QMJ, 161QMK, 152QMI, 1P61QMK, YN1P57QMJ, 1P52FMI, 154FMI, JJ157QMJ, 1P57QMJ, BN157QMJ, BN161QMK-A and similar QMJ / QMK / QMI engines.

Important Things to Note

• If your engine code includes “QM” or “FM”, this kit is generally compatible.
• Works best when combined with a performance head and exhaust for optimal airflow.
• This kit upgrades the cylinder only — your stock head must be reused or upgraded.
• Performance parts are intended for off-road / closed-course use where applicable.

Not sure about fitment? Send us your engine code and we’ll verify compatibility before you order.

What's Included

• 61mm NCY Cylinder (171.3 cc)
• Lightweight piston
• Piston rings
• Wrist pin + circlips
• Base gasket + head gasket

Ready to install onto compatible GY6/Genuine engines — no case cutting required.