Recommended Additional Upgrades
01
S1 FL 30th Anniversary Special Edition
Get the Combo set for the ultimate brake system upgrade.
The RCB Chain Sprocket E-Series (428-14T) is a high-durability front engine sprocket designed specifically for the Yamaha 155cc platform. While the stock sprocket is designed for general longevity, the E-Series focuses on reduced friction and high-tensile strength to handle the rapid torque delivery of the R15’s VVA engine.
The 14T (14-Tooth) size is the standard front fitment, maintaining the factory gear ratio for a perfect balance between quick acceleration and top-speed cruising.
Key Features
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High-Carbon Steel Construction: Forged from high-grade carbon steel that has undergone a specialized heat treatment process. This ensures the teeth remain sharp and do not “hook” or wear down prematurely under heavy loads.
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Precision CNC Machining: Every tooth is precision-cut to ensure perfect engagement with the chain. This reduces mechanical “slap” and noise, providing a smoother power transfer from the engine to the rear wheel.
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428 Pitch Standard: Built to the 428-pitch specification, making it a direct plug-and-play replacement for the Yamaha R15 V3, V4, and M models. It is fully compatible with both standard and O-ring/X-ring chains.
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Induction Hardened Teeth: The tips of the teeth are induction hardened to resist the immense friction generated at high RPMs, ensuring that the sprocket can withstand thousands of kilometers of spirited riding.
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Lightweight Design: Optimized to remove unnecessary mass without compromising structural integrity, reducing the “rotational unsprung weight” of the drivetrain.
Technical Specifications
| Feature | RCB E-Series Sprocket Details |
| Size / Teeth | 14T (Front/Engine Sprocket) |
| Chain Pitch | 428 |
| Material | Heat-Treated High-Carbon Steel |
| Compatibility | Yamaha R15 V3, R15 V4, R15M, MT-15, XSR 155 |
| Series | E-Series (Endurance & Efficiency) |
Why Choose the RCB E-Series?
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VVA Engine Compatibility: The R15 engine delivers a sudden surge of power when the Variable Valve Actuation (VVA) kicks in. The E-Series sprocket is designed to handle this “hit” without stretching the chain or wearing out the tooth profile.
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Extended Chain Life: By ensuring a perfect tooth-to-link fit, this sprocket reduces the friction that causes chains to heat up and stretch.
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Reliability for Touring: For riders who take their R15 on long-distance trips, the E-Series offers peace of mind through its high resistance to “rounding off” in harsh conditions.
Installation & Maintenance Tip
When replacing your front sprocket, it is highly recommended to inspect your rear sprocket and chain as well. For the best performance and longest life, replace all three components as a set. Always ensure the locking plate and bolts are torqued correctly and use a high-quality chain lube to maintain the hardened coating of the teeth.
