Genuine Throttle Air Mixture Setting Screw for Yamaha R15 Series (SKU: CASYR15)

Micro-Calibrated Needle Taper: CNC-machined with a exact factory angle needle profile to deliver highly predictable mixture adjustments down to a quarter turn.

Vibration-Safe Element Profile: Built to seat perfectly alongside your high-tensile factory tension spring, soaking up engine resonance to prevent adjustment drift.

Premium Durable Composition: Forged from high-grade, wear-resistant materials to ensure threads won't bind or shear inside your aluminum throttle casing.

Restores Low-End Stability: Delivers a balanced, reliable air-fuel mixture during closed-throttle scenarios, cleaning up erratic low-RPM engine hesitation.

Pre-Fitted Rubber O-Ring Seal: Comes equipped with a tight-fitting nitrile rubber sealing ring to block performance-killing unmetered vacuum leaks from leaning out your engine.

Part No: 38B-E4147-00

Is your high-revving machine struggling with a erratic engine idle, cold start drops, or annoying hesitation when you roll on the throttle? Over time, engine vibrations can shake loose your air circuit settings, or heavy-handed adjustment can blunt the micro-tapered tip of your factory pilot screw—disrupting the fine fuel-air balance your engine relies on at lower RPMs.

The Throttle Air Screw for Yamaha R15 (SKU: CASYR15) is a premium, precision-engineered component built exactly to original factory dimensions. Operating within your throttle's low-speed bypass loop, it accurately meters air volume when the throttle slide is fully closed. Swapping out your worn screw for this fresh, OEM-spec replacement cleans up your off-idle engine performance, eliminates deceleration popping, and keeps your idle rock-steady.