Polini
Polini Performance Torque Spring: Yamaha Zuma 50
Description
Eliminate mid-range transmission lag and prevent belt slippage with the premium Polini Performance Clutch Torque Spring. Engineered and manufactured in Italy by the tuning legends at Polini, this counter-pressure spring runs exactly 15% stiffer than your stock factory unit. By applying precise, constant lateral pressure against the rear pulley sheaves, it keeps your drive belt loaded tightly within the optimal powerband—maximizing out-of-the-hole acceleration and sharpening throttle response during heavy corner exits or hill climbs.
Advanced CVT Tuning Features
- 15% Stiffer Compression Rate: Perfectly calibrated to raise your shifting RPM just enough to bypass factory flat spots, keeping your 50cc engine pinned squarely inside its peak power band.
- Premium Italian Craftsmanship: Wound from high-tensile, heat-treated silicon-steel alloy that resists spring sag, mechanical binding, and thermal fatigue under prolonged high-RPM stress.
- Responsive Back-Shifting: Drastically improves back-shift response when decelerating, delivering immediate engine engagement the millisecond you snap the throttle back open.
Comprehensive Fitment Guide
This performance spring features universal compatibility across Yamaha-based and Minarelli-clone 50cc scooter drivetrains:
| Make / Manufacturer | Model Family Compatibility | Engine & Platform Architecture |
|---|---|---|
| Yamaha | Zuma 50 / Zuma 50cc 2T | 2-Stroke (Horizontal & Vertical Minarelli Blocks) |
| Yamaha | Zuma 50F / 50FX / C3 / Vino | 50cc 4-Stroke (Liquid-Cooled 3-Valve Layouts) |
| Yamaha | Jog 50 / Jog RR | 50cc 2-Stroke Air & Liquid Cooled |
| Genuine Scooter Co. | Buddy 50 / RoughHouse 50 / Rattler 50 | 50cc 2-Stroke (Minarelli Horizontal Clone) |
| Aprilia | Scarabeo 50 2T / SR 50 (Minarelli) | 50cc 2-Stroke Minarelli Engine Baselines |
| Adly / Keeway / Eton | Beamer, Matrix, F-Act, Hurricane, Viper 50 | 50cc 2-Stroke (40QMB / Minarelli Clones) |
Technical Specifications
- Spring Rate Resistance: +15% Tension Increase Over OEM Stock
- Material Composition: High-Tensile Silicon-Steel Alloy
- Color Classification: Blue Tension Metric
- Country of Origin: Italy (IT)
- Manufacturer Part Number: 243.093 / 146-83
Tuning Note: Installing a stiffer torque spring alters your CVT balancing. If your transmission stays in a "low gear" ratio too long or over-revs, you may need to increase your roller weight mass slightly to perfectly counterbalance the new spring rate.
Installation Tip: The rear clutch pulley assembly is under heavy internal mechanical tension! Always use a dedicated clutch compressor tool when loosening the large retaining nut to prevent parts from flying off your workbench.
About Polini
Founded in 1950 in Alzano Lombardo, Italy, Polini Motori has spent over 70 years engineering high-performance components for small-displacement engines. From racing carburetors to CVT tuning kits, Polini parts are trusted by mechanics and enthusiasts worldwide for their precision manufacturing and consistent quality.
SKU: 146-83 | Vendor: Polini | Category: CVT Springs & Transmission
Product Diagrams
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30-day return period on eligible items
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