420-12T Front Engine Sprocket (17mm) for 50cc–150cc Dirt Pit Bike & ATV

Product Overview

Optimize your gear ratio with this 420-12T Heavy-Duty Front Sprocket, specifically designed for the standard 17mm output shaft found on most 50cc to 150cc horizontal engines. Crafted from high-grade steel and subjected to specialized heat treatment, this sprocket is built to endure the high-torque demands of off-road riding. Whether you are upgrading a pit bike or repairing an ATV, this 12-tooth configuration offers a perfect balance of low-end torque and mid-range speed.

Product Compatibility

Component Type	Specification
Engine Displacement	50cc, 70cc, 90cc, 110cc, 125cc, 140cc, 150cc
Vehicle Types	Pit Dirt Bikes, Motorcycles, ATVs, 4-Wheelers
Chain Pitch	420
Shaft Fitment	17mm Countershaft (Standard Small Displacement)
Common Engines	Lifan, YX, Zongshen, Loncin, TaoTao

Specifications

Feature	Details
Model	420 Style / 12 Teeth
Inner Diameter	17mm (0.67")
Mounting Hole Distance	30mm (1.18") center-to-center
Material	Heat-Treated High-Carbon Steel
Package Includes	1 x Sprocket, 1 x Retainer Clip (Holder), 2 x Bolts

Key Features

• Complete Installation Kit: Unlike standard sprockets, this package includes a free retainer holder and mounting bolts, allowing for a complete and secure installation right out of the box.
• Heat-Treated Steel Construction: The steel is "hot-treated" to increase surface hardness, ensuring the teeth resist rounding and wear even when subjected to the abrasive sand and mud of dirt tracks.
• Precision 12-Tooth Design: Sized for 420 chains, the 12T geometry provides a mechanical advantage that improves acceleration compared to larger sprockets, making it ideal for technical trails.
• Universal 17mm Fitment: Designed to fit the most common small-engine output shafts, featuring a 30mm bolt-hole spacing compatible with standard sprocket locking plates.
• Long-Term Durability: Engineered for high-mileage use, the robust construction maintains its structural integrity under high-RPM operation, reducing chain slap and improving drivetrain stability.