63mm Big Bore Cylinder Kit with Rocker Arm & 94-Link Chain for 4-Stroke GY6 150cc 180cc 200cc Upgrade

Product Overview

Push your GY6 engine to its absolute limit with the GOOFIT 63mm Extreme Big Bore Kit. This high-performance assembly is designed to transform standard 150cc engines into high-torque 180cc/200cc powerhouses. Unlike basic kits, this "Professional Series" includes a precision-matched rocker arm assembly and a heavy-duty 94-link timing chain to ensure your valve train can handle the massive increase in displacement. Perfect for off-road ATVs, high-speed scooters, and racing go-karts.

Product Compatibility

A premium performance upgrade for the GY6 150cc (157QMJ) platform and its high-displacement variants.

Original Engine	Upgrade Potential	Recommended Application
GY6 150cc	Upgrades to 200cc	Racing Scooters & Quads
GY6 180cc / 200cc	Direct Replacement	High-Load Off-Road Use
Compatible Vehicles	ATVs, Go Karts, Buggies	TaoTao, Coolster, Ice Bear

Specifications

Attribute	Details
Cylinder Bore	63mm / 2.48" (Extreme Big Bore)
Intake Port	Dia: 26mm (Bolt Spacing: 45mm)
Exhaust Port	Dia: 30mm (Bolt Spacing: 50mm)
Timing Chain	94 Links (High-Strength)
Material	Aerospace-Grade Aluminum Alloy
Kit Includes	Cylinder, Rocker Arm Assembly, 94-Link Chain, Piston Kit, Gaskets

Key Features

• Massive Displacement Boost: The 63mm bore provides a significant increase in raw horsepower and low-end torque, essential for heavy-duty off-roading and uphill climbing.
• Precision Rocker Arm Assembly: Includes a pre-adjusted rocker arm set that ensures exact valve timing and reduced friction, preventing "valve float" at high RPMs.
• Heavy-Duty 94-Link Timing Chain: Specifically selected for extended-deck or high-performance GY6 configurations, providing reliable synchronization between the crank and cam.
• Advanced Aluminum Heat Dissipation: The high-strength alloy body rapidly dissipates heat, maintaining engine stability and preventing power loss during long-distance, high-speed operation.
• Fuel-Efficient Power: Optimized combustion chamber design increases the compression ratio and combustion efficiency, delivering more "bang for your buck" with every drop of fuel.