Moto Tassinari VForce4R Reed Valve Set V4R04 — Yamaha YZ125 / YZ125X 2005-2026

Product Description

The Moto Tassinari VForce4R V4R04 is the ultimate intake upgrade for riders looking to unlock the full potential of their Yamaha YZ125 and YZ125X. Designed with a clean-sheet approach, this system features an all-new manifold, reed cage, and air guide, specifically engineered to provide a 10.5% increase in combined reed tip area. By reducing the frontal area of the central wing by 15.6% and utilizing optimized airfoil shapes, the VForce4R significantly improves air velocity and total airflow for crisp, immediate throttle response across the entire RPM range.

Engineered for professional-level durability, the VForce4R introduces advanced features like long reed stops that progressively slow petal tip velocity, greatly extending the life of the carbon fiber reeds. The cage tips feature rubber overmolding to dampen impact, while the pre-curved reed petals ensure an airtight seal at the tip to eliminate power-robbing blowback. Proudly made in the USA, this reed valve set is the industry standard for 2-stroke engine efficiency.

Top Features: Moto Tassinari VForce4R

• Increased Airflow: 10.5% larger reed tip area for superior power delivery.
• Enhanced Durability: Long reed stops and rubber overmolding protect petals from high-speed fatigue.
• Aerodynamic Engineering: Reduced central wing area and airfoils increase air velocity.
• Precision Sealing: New carbon fiber resin system with pre-curved petals ensures a perfect seal.
• Complete Upgrade: Includes all-new manifold, reed cage, and air guide for a perfect fit.

Please review the detailed compatibility data below to ensure an exact fitment match for your motorcycle before finalizing your purchase.

Fitment List

Frequently Asked Questions

Q: Is this a direct bolt-on upgrade?
A: Yes, the V4R04 is designed to bolt directly onto your Yamaha YZ125/YZ125X intake tract without requiring any permanent modifications to your engine cases.

Q: How often should I inspect the reed petals?
A: We recommend checking your reed petals during every top-end refresh. If you notice any fraying, chipping, or if they no longer seat perfectly flat against the cage, it is time for a replacement set.

Expert Pro-Tip: When installing the VForce4R, always inspect your intake boot for dry rot or cracks. A small leak in the intake boot will lean out your jetting and potentially damage your top-end. Ensure all mounting surfaces are clean and the hardware is tightened evenly in a cross pattern to prevent air leaks.

Recommended Pairings:
o Yamaha YZ125 Performance Parts & Upgrades
o Yamaha 2-Stroke Performance Parts
o Essential Intake Maintenance Tools

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