Description
Yamaha Blaster VForce 4 Reed Valve System
The Yamaha Blaster VForce 4 Reed Valve System is a proven performance upgrade for the 1988–2006 Yamaha YFS200 Blaster. Manufactured by Moto Tassinari, the VForce 4 is designed to improve airflow, throttle response and power delivery throughout the engine’s operating range.
Unlike a conventional reed cage, the VForce design provides additional reed-tip area and more efficient airflow into the engine. This allows the reeds to respond quickly to changes in pressure while helping the engine fill the crankcase more effectively.
Whether you have a stock Yamaha Blaster, a bolt-on trail machine or a ported performance engine, the VForce 4 reed valve helps the engine respond more quickly when you open the throttle.
Redesigned VForce 4 Reed Cage
The VForce 4 is a complete redesign of the earlier VForce 3 system. Its reed cage incorporates an airfoil-shaped reed-tip area that increases air velocity through the outer ports.
Moto Tassinari also reduced the frontal area of the center wing by 15.6% and gave it a more aerodynamic shape. These changes reduce airflow restriction and provide a cleaner path for the incoming fuel-and-air mixture.
The combined reed-tip area has been increased by more than 10%, allowing the Yamaha Blaster VForce 4 Reed Valve to flow more air than the previous design.
Pre-Curved Carbon-Fiber Reed Petals
The VForce 4 uses pre-curved carbon-fiber reed petals manufactured with an updated resin and lay-up system. The pre-curved design helps the petals seal tightly against the reed cage, particularly at the tips.
Better reed sealing can improve starting, low-speed response and throttle control. Longer reed stops progressively slow the reed petals as they open, helping reduce stress and increase petal durability.
Performance Benefits
Installing a Yamaha Blaster VForce 4 can provide several performance advantages:
- Quicker throttle response
- Improved airflow into the engine
- Stronger low- and midrange response
- Smoother power delivery
- Better reed-tip sealing
- Increased reed-petal durability
- Improved performance on stock and modified engines
The exact performance improvement will depend on the engine combination, including the carburetor, exhaust system, air filter, porting and cylinder-head setup.
Yamaha Blaster Fitment
This Moto Tassinari VForce 4 reed valve is designed for:
- 1988 Yamaha Blaster YFS200
- 1989–2002 Yamaha Blaster YFS200
- 2003–2006 Yamaha Blaster YFS200
It can be used with the stock Yamaha Blaster carburetor and many common aftermarket carburetor combinations. Always confirm that the intake boot, carburetor and clamps are properly fitted before operating the engine.
Installation and Jetting
The VForce 4 installs in place of the original Yamaha Blaster reed cage. Inspect the intake gasket and intake boot during installation, and replace any damaged or hardened components. Tighten the intake fasteners evenly and perform a leak-down test after installation whenever possible.
Increasing airflow can affect the engine’s fuel requirements. Check the carburetor jetting after installing the VForce 4, especially when the engine also has an aftermarket pipe, open airbox, larger carburetor, ported cylinder or modified cylinder head.
A two-stroke engine should never be operated with an intake leak or excessively lean jetting.
Genuine Performance for the Yamaha Blaster
The Yamaha Blaster VForce 4 Reed Valve is an excellent upgrade for riders looking for better throttle response and improved airflow without modifying the cylinder. Order yours from Ken OConnor Racing and build your Yamaha Blaster with parts selected by an experienced engine machine shop and Yamaha Blaster specialist.
Product specifications
| Specification | Details |
|---|---|
| Brand | Moto Tassinari |
| Product | VForce 4 reed valve system |
| Vehicle | Yamaha Blaster YFS200 |
| Fitment | 1988–2006 |
| Reed material | Carbon fiber |
| Installation | Replaces the stock reed cage |
| Engine type | Two-stroke |
