NCY Engine Case Boring Tool - GY6 125/150cc

Engine Builder Precision: NCY GY6 Case Boring Tool

Push the limits of your GY6 engine with the NCY Case Boring Tool. When upgrading to extreme big-bore kits (such as 61mm or 63mm cylinders), the stock engine case diameter is often too small to accept the larger cylinder skirt. This professional-grade tool allows you to precisely machine the engine case to the perfect clearance, ensuring a seamless fit for high-displacement performance upgrades.

Technical Performance Features

• Professional Machining at Home: Designed to eliminate the need for expensive machine shop services, allowing builders to bore their own cases with precision and consistency.
• Adjustable Cutting Diameter: Engineered specifically for GY6 125cc and 150cc (QMI152/QMJ157) engine blocks to facilitate 170cc, 180cc, and larger conversions.
• Guided Stability: The tool's pilot design ensures the bore stays perfectly centered with the crankshaft axis, preventing sleeve misalignment and potential engine failure.
• Hardened Steel Cutting Bit: Features a durable, high-speed steel cutter capable of shaving through cast aluminum cases with minimal heat buildup.

Comprehensive Fitment Guide

This specialized tool is compatible with a wide range of GY6-based and Taiwanese-manufactured engines, including:

• Not compatible with crankcases with 57mm stud spacing

Specifications

• Engine Type: GY6 125cc - 150cc (4-Stroke)
• Tool Type: Manual Case Boring / Machining
• Manufacturer: NCY (Made in Taiwan)

Mechanic's Note: Case boring is a critical process. For the best results, AZScooterParts recommends using a drill press or a high-torque hand drill equipped with a clutch to prevent binding. Always clear aluminum shavings thoroughly from the crankcase before reassembly to prevent bearing damage.

Part Number: 1400-1015
Certification: ISO 9001 Certified

The NCY Case Boring Tool is a must for most large bore projects on GY6 cylinders (up to 67mm) and other model cylinders (up to 72mm). 

• Not compatible with a 57mm stud spacing crankcase

Model Fitment