V-Force (VF4) Yamaha YZ85 02-22

Applications: Yamaha YZ85
Model Years: 1993-2020

The new YZ85 VForce4Ri utilizes a custom intake manifold boot that offers a straighter shot to the intake that greatly enhances both airflow and performance. The VForce4Ri also incorporates carbon fibre reed petals designed to ensure superior reliability and maximum performance.

All “R” models include a rubber overmolded pad on the reed tip area of the reed cage to significantly improve reed petal life.

The unique design of the VForce reed valve system features double the reed tip surface over a conventional reed valve design. This has two major benefits: 1) The reed petals only travel half the distance as a conventional reed valve design to get the same airflow. 2) Because the reed petals only need to travel half the distance of that on a conventional reed valve design, there is a greater chance of them being fully opened as well as a better chance of sealing when they are "closed". A reed petal never truly "closes" in a classic sense, as it is always in movement. Consider this, an engine operating at 8,000 RPM results in a reed petal opening and closing 133 times in one second. This fact, sheds light on another VForce advantage. Since the petals are only traveling half the distance, they generally last longer as they receive less wear than the reed petals on a conventional reed valve design.

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 fibre 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 overmolding 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

WHAT'S INCLUDED WHEN I PURCHASE THE VFORCE4RI REED VALVE SYSTEM?

Moto Tassinari and VForce4R decals, detailed installation instructions, complete VForce4Ri reed valve system (including reed petals), custom intake manifold boot and gaskets.