NCY 1500 RPM Contra Spring GY6 CVT | 125cc 150cc 157QMJ

Fine-tune your CVT transmission's shift point and eliminate belt slip with the NCY 1500 RPM Contra / Compression Spring for GY6 engines. Engineered for the rear clutch pulley, this performance spring is a direct upgrade for riders looking to optimize acceleration on 125cc, 150cc, 169cc, and 171cc GY6-based scooters.

Key Features

• Prevents belt slip by increasing lateral pressure on the drive belt
• Raises CVT shift point for optimized acceleration at higher RPM
• 1500 RPM rating — stiffer than stock for performance-oriented tuning
• ISO 9001 certified manufacturing
• Made in Taiwan

Specifications

• Wire Diameter: 4.2mm
• Inner Diameter: 48.5mm
• Length: 154.0mm
• RPM Rating: 1500 RPM

Compatibility

Fits 157QMJ-based 125cc / 150cc / 169cc / 171cc GY6 engines with the following engine codes:

Mechanic's Notes

Compression springs (also called contra springs) serve two functions: they apply lateral pressure on the drive belt to prevent slip, and they control the RPM at which the CVT transitions from lower to higher gear ratios.

For optimum acceleration, match the clutch pulley transition RPM to your engine's peak power band. If your engine peaks at 7500 RPM but your spring transitions at 6000 RPM, you're leaving performance on the table.

• Stiffer Spring = More belt tension + higher RPM transition
• Softer Spring = Less belt tension + lower RPM transition

This spring is also available as part of our Stage 1 GY6 150 Performance Kit.

This product is intended for off-road use only. Not intended for use on public roads. Not legal for use in California.

California Prop 65 Warning: www.p65warnings.ca.gov

• 1500 RPM contra/compression spring — raises CVT shift point for performance-oriented tuning
• Prevents belt slip by increasing lateral pressure on the drive belt
• Stiffer than stock — optimizes acceleration at higher RPM
• ISO 9001 certified, made in Taiwan by NCY since 1997
• Fits GY6 157QMJ-based 125cc–171cc engines

RPM Rating: 1500 | Wire Diameter: 4.2mm | Inner Diameter: 48.5mm | Length: 154.0mm | ISO 9001 Certified | Weight: 0.27 lbs | MPN: 660A09GY615 | Origin: Taiwan | SKU: 1200-1027

GY6 157QMJ / 161QMK / 152QMI / 1P61QMK / YN1P57QMJ / 1P52FMI / 154FMI / JJ157QMJ / 1P57QMJ / BN157QMJ / BN161QMK-A and other QMJ/QMK/QMI 125cc-171cc engines | Genuine Buddy 125/150/170i | SYM / Wolf / Bintelli / BMS / TaoTao / Jonway and other GY6 125-150cc scooters