Boyesen Rad Valve System
MSRP: $189.95
$151.96
Exact Fitment Guarantee
The Boyesen Rad Valve System is a complete, high-performance aerodynamic intake and reed valve assembly engineered to replace restrictive OEM reed blocks on modern two-stroke motocross and off-road motorcycles. Factory reed blocks feature flat, boxy intake runners that create severe boundary-layer turbulence, dead air pockets, and uneven fuel distribution across the intake tract. The Boyesen Rad Valve eliminates this restriction with a one-piece cast aluminum housing featuring aerodynamic surface profiling and multi-stage aerospace carbon reed petals.
The internal architecture of the Rad Valve incorporates Boyesen's patented Aerodynamic Surface Optimization (ASO). The intake tract is precision-tapered and contoured with continuous curvature, accelerating intake charge velocity and directing fuel-air mixture smoothly into both the upper and lower crankcase transfer ports. The system utilizes Boyesen's multi-stage Pro Series carbon fiber reed petals: a lightweight top petal responds instantly to low-RPM vacuum pulses for razor-sharp bottom-end throttle snap, while a stiffer secondary petal opens at high RPM to deliver maximum volumetric airflow without reed flutter. On the track, riders experience instantaneous throttle response out of corners, eliminated low-end hesitation, and stronger mid-to-top over-rev.
- Body Construction: One-piece aerodynamic cast aluminum intake housing
- Reed Petals: Dual-stage aerospace carbon fiber Pro Series matrix
- Airflow Optimization: Patented Aerodynamic Surface Optimization (ASO) interior porting
- Gasket System: High-density composite crankcase sealing gasket included
- Maintenance: Replaceable reed petal packs available for routine servicing
### Step-by-Step Installation & Safety Protocols Installation requires approximately 30-45 minutes. Remove the seat, subframe bolts, and loosen the carburetor/throttle body airboot clamps. Pivot the subframe back to gain access to the intake manifold. Remove the four bolts securing the stock reed cage to the engine crankcase. Discard the old gasket and thoroughly clean the crankcase mounting surface of old sealant. Install the Boyesen Rad Valve using the supplied high-grade gasket, taking care not to touch the carbon reed petals with oily fingers. Reinstall the mounting bolts with blue thread locker and torque in an X-pattern to 8-10 Nm (do not over-tighten, which can distort the reed cage sealing face). Reconnect the intake boot and subframe, verifying an airtight seal around all boots.
### Maintenance & Reed Inspection Protocol Maintenance involves periodically inspecting reed petals for chipping, fraying, or light gaps by holding the valve up to a light source. Replace reed petals if gaps exceed 0.015 inches or after 40-50 hours of competitive two-stroke racing.
Frequently Asked Questions
Q: How does the one-piece aluminum Rad Valve differ from a plastic reed cage?
A: The solid cast-aluminum body maintains its exact aerodynamic shape without flexing under high engine vacuum or warping from engine heat, ensuring consistent reed sealing and precise airflow velocity.
Q: Do I need to change carburetor jetting when installing the Rad Valve?
A: Because the Rad Valve dramatically improves intake velocity and atomization, you may find the low-end throttle response is so efficient that the air screw or pilot jet needs slight adjustment (often 1/2 turn on the air screw) to achieve perfection.
Q: Are the carbon fiber reed petals replaceable?
A: Yes. Boyesen manufactures direct-fit replacement Pro Series carbon reed petal kits, allowing you to refresh the valve without purchasing a complete new intake assembly.
Q: Will the Rad Valve fit fuel-injected two-strokes (TPI / TBI)?
A: Yes, Boyesen produces model-specific Rad Valves engineered to match the intake throttle body manifolds of modern fuel-injected two-stroke machines.