KTM SX85 (2005-2022) V-Force Reed Valve System

KTM SX85 (2005-2022) V-Force Reed Valve System

Designed for KTM 85cc & 105cc and Husqvarna 85cc models, the VForce4R (VF4R) offers enhanced reed petal durability thanks to its rubber overmoulded reed cage tips and extended reed stops. It also includes all the benefits of the unique VForce reed valve design.

Unique VForce Reed Valve Design

The VForce reed valve system doubles the reed-tip surface area compared to conventional designs, delivering two major advantages:

• Reduced Reed Travel: The reed petals only travel half the distance required in a conventional reed valve, achieving the same airflow.
• Improved Performance: With reduced travel, the reed petals are more likely to fully open and seal effectively when “closed.” As an engine running at 8,000 RPM opens and closes the reeds 133 times per second, reduced travel decreases wear, extending reed life.

Standard VForce Reed Valve Features:

• Double the reed-tip surface of conventional designs.
• Increased bottom-end, stronger mid-range, and extended top-end power.
• Improved efficiency through reduced reed petal travel.
• Increased airflow for greater horsepower.
• Reduced reed petal wear.
• Screw-free design eliminates the risk of screws entering the motor and enables rapid reed petal changes.

Improved VF4 Features:

• All-new reed petal resin system, carbon fibre, and lay-up.
• Pre-curved reed petals for improved sealing at the tips.
• Wider reed cage for maximum airflow.
• 10.5% increase in total reed tip surface area for enhanced airflow.
• Airfoil-shaped cage tips to increase air velocity from outer ports.
• Long reed stops to slow petal tip velocity progressively, improving durability.
• 15.6% reduction in the frontal area of the central wing, combined with a more aerodynamic design.

All-New VF4R Features:

• Rubber overmoulding on the reed tip surface of the cage for enhanced petal life.
• Extended reed petal stops for improved durability.
• Pre-curved reed petals for better sealing at the tips.