V-Force 4 Reed Valve YZ250/X

The all-new VFORCE4X for the Yamaha YZ250 and YZ250X motorcycles has been designed to offer you exceptional durability and overcome the shortcomings of the stock reed valve system.

The VForce reed valve system by Moto Tassinari has been the reed valve system of choice by anyone serious about two-stroke engine performance for the last 25+ years. The simple premise of the VForce reed valve system is to increase engine power and throttle response by increasing the efficiency over a conventional reed valve design by doubling the reed-tip surface.

STANDARD VFORCE REED VALVE FEATURES

• Double the reed tip surface over a conventional reed valve design
• Increased bottom end, stronger mid-range and longer top-end
• Greater efficiency due to reduced reed petal travel
• More airflow means more horsepower
• Reduced reed petal wear
• Screw free design eliminates risk of screws going through motor
• Screw free design enables rapid reed petal changes

IMPROVED VFORCE4 FEATURES

• All-new reed petal resin system, carbon fiber and lay-up
• Pre-curved reed petal ensures better seal at tip
• Wider reed cage for maximum airflow
• Combined reed tip area increased by 10.5% resulting in increased total air flow
• Airfoil shape added to cage tip to increase air velocity from outer ports
• Long reed stops added to progressively slow petal tip velocity, for increased petal durability
• Reduced frontal area of central wing by 15.6% combined with a more aerodynamic shape

ALL-NEW VFORCE4R FEATURES

• Rubber overmodling on reed tip surface of cage to further enhance petal life
• Pre-curved reed petal ensures better seal at tip

ALL-NEW VFORCE4RI FEATURES

• Custom intake manifold boot that offers a straighter shot to the intake that greatly enhances both airflow and performance

FITS

YAMAHA YZ250/X (1997-2024)