NCY Compression Spring (Performance); Yamaha Zuma 125 2022+

The NCY Compression Performance Springs (also known as contra or torque springs) are installed in the driven pulley of your Yamaha Zuma 125's continuously variable transmission (CVT). They work by applying counter pressure against the variator's roller weights, controlling how quickly the belt shifts positions to change gear ratios. Here's a breakdown of the benefits:

• RPM Rating and Stiffness: The RPM number indicates the spring's stiffness—1000 RPM is the softest (similar to stock for many models), 1500 RPM offers medium stiffness, and 2000 RPM is the stiffest. A stiffer spring (higher RPM) resists the driven pulley's compression more, keeping the transmission in a lower gear ratio longer. This allows the engine to build more RPM and torque before upshifting, resulting in sharper acceleration and better low-end power.
• Acceleration Gains: With a higher-rated spring like the 2000 RPM, your Zuma will launch harder from a standstill and pull stronger through the mid-range, as the engine stays at peak power RPMs longer. The 1500 RPM provides a noticeable boost over stock without being too aggressive, while the 1000 RPM prioritizes smoother, earlier shifts for efficient cruising.
• Tuning Flexibility: These springs help customize your scooter's behavior. For example, pairing a stiffer spring with lighter roller weights or a performance variator can optimize for top speed or torque, depending on your setup. They also improve back-shifting (downshifting) during deceleration, ensuring quicker response when you roll on the throttle again.
• Overall Ride Improvement: By fine-tuning shift points, these springs reduce belt slip, enhance throttle response, and can even extend the life of CVT components under performance demands. Note that for maximum gains, they pair well with other NCY upgrades like clutch kits or exhausts. Always consult a mechanic for installation if you're new to scooter mods, and test in a safe environment to dial in your preferred feel.