RCB E2 SERIES BRAKING SYSTEM
RCB S1 SERIES BRAKING SYSTEM
Recommended Additional Upgrades
01
Uma Laser Iridium Spark Plug
Improve ignition with Uma Racing Laser Iridium Spark Plug.
03
Uma Racing Engine Oil
Get smoother engine performance with Uma Racing Full Synthetic Engine Oil.
The UMA Racing Silent Timing Chain (96L) is a high-precision, heavy-duty replacement for the factory cam chain on Yamaha’s 155cc VVA engine platform. It is engineered to deliver precise valve timing, reduced mechanical noise, and exceptional stretch resistance under high-RPM conditions.
The 96-link (96L) length makes it an exact drop-in replacement for the Yamaha R15 V3, R15 V4, and R15M, as well as other shared-engine models like the MT-15 and WR155R.
Key Features
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Premium Japanese Steel & Material: Manufactured using ultra-high-grade alloy steel that has undergone specialized heat treatment. This increases tensile strength and minimizes physical wear on the pins and link plates.
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Advanced Silent Link Design: Features a specialized link plate profile designed to engage the crankshaft and camshaft sprockets seamlessly. This minimizes the “whining” or clicking mechanical noise common in high-mileage or high-stress engines.
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Anti-Stretch Engineering: High-performance engines running Variable Valve Actuation (VVA) place a variable load on the valvetrain. UMA’s pre-stretched link architecture resists elongation over time, ensuring your valve timing remains perfectly dialed in.
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Low Friction & High Efficiency: The precision-ground pins are treated with a low-friction coating. This reduces internal drivetrain drag, allowing the engine to rev more freely while generating less internal heat.
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Perfect Sync for Performance: Essential for maintaining dead-accurate synchronization between the crankshaft and the cylinder head. Even a millimeter of timing chain stretch can retard valve timing, leading to lost horsepower and poor throttle response.
Technical Specifications
| Feature | UMA Silent Timing Chain Details |
| Link Count | 96 Links (96L) |
| Engine Application | 155cc 4-Valve VVA LC Engines |
| Compatible Models | Yamaha R15 V3 / R15 V4 / R15M / MT-15 / XSR155 |
| Material | High-Tensile Heat-Treated Alloy Steel |
| Type | Silent / Bushless Chain Architecture |
Why Upgrade to the UMA 96L Timing Chain?
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Crucial for Big-Bore Kits: If you have upgraded your engine with a big-bore kit (such as a 63mm block), a high-lift camshaft, or stiffer valve springs, the load on your valvetrain increases exponentially. The stock chain can stretch quickly under these loads; the UMA chain is built to handle the extra stress.
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Eliminates Timing Slack: As a stock chain wears down, it develops slack that the automatic chain tensioner can no longer compensate for. This results in an annoying ticking sound from the right side of the engine. The UMA chain permanently resolves this issue.
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Tracks and Aggressive Riding: Constant high-RPM riding and quick shifts put sudden snapping forces on the timing apparatus. This chain is built to endure racing environments, providing peace of mind during spirited runs.
Maintenance & Installation Tip
When replacing a timing chain, it is highly recommended to inspect the condition of your Timing Chain Guides/Sliders and the Automatic Chain Tensioner. If the guides are deeply grooved or the tensioner spring has weakened, replace them alongside the new UMA chain to ensure optimal chain alignment and tension.
