Primary Clutch Spring for Polaris Boost (RMK Sled Only) - 140-300 // SKU: 05-140-300

SKU: 05-140-300
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$27.95 USD
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Primary Clutch Spring (140-300) for Polaris Patriot RMK Boost // SKU: 05-140-300

IMPORTANT FITMENT NOTE: Designed specifically for Polaris Patriot RMK Boost Mountain Sleds ONLY. Will NOT fit trail boost models (Indy Boost, Switchback Boost, VR1 Boost).

Fine-tune your clutch engagement and maintain consistent peak shift RPM in deep powder with the Bikeman Performance 140-300 Primary Clutch Spring for Polaris Patriot RMK Boost snowmobiles. The primary clutch spring plays a vital role in controlling how and when your drive clutch engages, as well as managing primary upshift force under heavy boost loads in steep, high-elevation terrain.

Featuring a 140 lb initial load and a 300 lb finish load, this spring profile delivers smooth, predictable engagement that prevents track trenching in soft snow, while the 300 lb finish load holds target operating RPM without over-revving or fading during long mountain pulls. Constructed from premium high-tensile spring steel, it resists heat sag and rate loss through extreme backcountry abuse.

Key Performance Features

  • RMK Mountain Boost Calibration: Engineered specifically to complement the horsepower curve, elevation dynamics, and track resistance of deep-snow Patriot Boost RMK models.

  • 140-300 Spring Rate Curve: 140 lb initial load prevents aggressive track trenching on take-off, while the 300 lb finish load maintains peak horsepower at full shift.

  • Holds Target Peak RPM: Prevents belt slippage and RPM fade on steep, high-load powder climbs under full turbo boost.

  • High-Tensile Alloy Steel: Built to endure rapid compression cycles, intense vibration, and severe underhood temperatures without losing rate profile over time.

Product Specifications

  • SKU: 05-140-300

  • Compatibility: Polaris Patriot RMK Boost Sleds ONLY (Matryx Mountain Chassis)

  • Fitment Exclusion: Does NOT fit trail boost models (Indy Boost, Switchback Boost, VR1 Boost)

  • Spring Rate: 140 lb Initial Load / 300 lb Finish Load

  • Component Type: Primary Drive Clutch Spring

  • Primary Function: Manages engagement RPM, upshift rate, and peak shift RPM control for mountain boost setups