V-FORCE V4R85A Moto Tassinari Reed Valve Ktm/husqvarna

( Brand: V-force ), ( Manufacturer Part Number: V4R85A ), ( Part Type: Valve )

Review V FORCE By Moto Tassinari 4r Reed Valve System #v4r85a Ktm/husqvarna

The **V-Force V4R85A Moto Tassinari 4R Reed Valve** is a high-performance, precision-engineered exhaust system meticulously crafted for the modern off-road enthusiast seeking uncompromising power, responsiveness, and durability. Designed exclusively for the **KTM 450/500 SX-F, 450/500 EXC-F, and Husqvarna TE 450/500 models**, this aftermarket exhaust system represents the pinnacle of Italian engineering, blending the legendary craftsmanship of **Moto Tassinari** with the aggressive, high-revving nature of the 4R85A reed valve setup. The **V4R85A** is not merely an upgrade it s a transformative component that redefines the throttle response, mid-range punch, and top-end acceleration of your bike, making every twist of the wrist feel immediate and exhilarating.

At its core, the **V-Force V4R85A** features a **dual-chamber, dual-pipe design** with **stainless steel construction**, ensuring both structural integrity and resistance to corrosion, even under the harshest off-road conditions. The **4R reed valve system** a hallmark of Moto Tassinari s expertise optimizes airflow at high RPMs, eliminating the dreaded "reed lag" that plagues stock setups. This allows the engine to breathe freely, unlocking **significant horsepower and torque gains** while maintaining a linear, aggressive power delivery that thrives in both trail riding and aggressive racing scenarios. The **custom-tuned exhaust headers** incorporate **precision-machined baffles and optimized diameter transitions**, ensuring a seamless exhaust pulse that maximizes scavenging efficiency and reduces backpressure, resulting in a **sharper, more aggressive exhaust note** that turns heads on the trail.

The **V4R85A** is engineered with **minimal weight** in mind, utilizing **thin-walled stainless steel tubing** and **lightweight clamps** to reduce unsprung mass without sacrificing strength. This not only enhances handling agility but also contributes to a more responsive ride, allowing the bike to corner with precision while still delivering the raw power needed for aggressive riding. The system is **fully compatible** with the stock airbox and intake, requiring no additional modifications, though pairing it with a **high-flow air filter** (such as a K&N or Motecc) can further enhance performance. For those pushing the limits, the **V-Force V4R85A** can be paired with a **downpipe cut-and-weld or slip-on muffler** for a more aggressive sound and additional power gains, though the stock muffler remains a popular choice for those who prioritize a balanced, race-ready setup.

Beyond its performance benefits, the **V-Force V4R85A** is a **styling statement**, featuring a **bold, aggressive profile** that accentuates the sporty lines of the KTM and Husqvarna platforms. The **high-quality powder-coated finish** ensures a durable, corrosion-resistant exterior that maintains its showroom shine even after years of rugged use. Whether you re carving through technical singletrack, hitting the motocross track, or simply cruising for fun, this exhaust system delivers **unmatched performance, reliability, and aesthetic appeal**, making it an essential upgrade for any serious off-road rider. With **Moto Tassinari s reputation for precision and V-Force s commitment to innovation**, the **V4R85A** is more than just an exhaust it s a **game-changing performance solution** that pushes your bike to its full potential.

The **Moto Tassinari V-Force V4R85A** is a high-performance reed valve kit designed for KTM and Husqvarna air/oil-cooled single-cylinder engines, particularly those in the 450cc to 500cc range. Below is a detailed breakdown of its pros and cons, followed by a conclusion and recommendation.

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### **Pros of the V-Force V4R85A**

1. **Significant Power Increase**

The V4R85A is engineered to enhance airflow and combustion efficiency, leading to noticeable power gains often in the range of **10 20 horsepower** depending on the base engine and tuning. This makes it ideal for track use or aggressive riding where extra power is desired.

2. **Durability and Reliability**

Moto Tassinari is a well-established brand with decades of experience in high-performance engine components. The V4R85A is built with high-quality materials, including forged aluminum and precision-machined parts, ensuring longevity if properly maintained. Many users report reliable operation after extensive use, especially when paired with supporting modifications (e.g., upgraded clutch, exhaust, and fueling).

3. **Compatibility with Stock and Modified Engines**

The kit is designed to fit stock KTM and Husqvarna air/oil-cooled engines (e.g., 2012 2020 models) without major modifications to the crankcase or cylinder. It works well with both stock and aftermarket components, making it versatile for different builds. Some users also report success with minor engine tweaks (e.g., porting, camshaft upgrades) to further optimize performance.

4. **Improved Throttle Response and Mid-Range Power**

Reed valves enhance airflow at higher RPMs and improve mid-range torque, which can make the bike feel more responsive and engaging. This is particularly beneficial for bikes that struggle with stock power delivery, such as the KTM 450 SX-F or Husqvarna TE 450.

5. **Easy Installation**

Compared to more complex engine rebuilds (e.g., full cylinder porting or crankshaft upgrades), the V4R85A is relatively straightforward to install. It requires removing the stock reed assembly and carburetor, then bolting in the new kit. However, some mechanical skill is still necessary, and tuning may be needed afterward.

6. **Track and Street Dual-Purpose Potential**

While primarily a track-focused kit, the V4R85A can also be used for street riding, though it may require additional modifications (e.g., a larger carburetor, upgraded fueling, or a high-flow exhaust) to prevent running rich or stalling under varied conditions.

7. **Positive Community Feedback**

The kit has a strong following among KTM/Husqvarna enthusiasts, with many riders praising its ability to unlock significant power without requiring a full engine swap. Online forums (e.g., KTM Forums, Husqvarna forums) often highlight success stories, though individual results vary based on tuning and supporting mods.

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### **Cons of the V-Force V4R85A**

1. **Requires Supporting Modifications**

- **Upgraded carburetor** (e.g., Walbro 1000cfm or Keihin FCR) to handle increased airflow.

- **High-flow exhaust** (e.g., Akrapovic or Moto Tassinari s own exhaust systems) to scavenge exhaust gases efficiently.

- **Fueling upgrades** (e.g., larger fuel tank, fuel pump, or direct port injection if converting to EFI).

- **Clutch and transmission upgrades** to handle the extra torque, as stock components may wear out prematurely.

Without these, the bike may run poorly, stall, or suffer from poor throttle response.

2. **Potential for Rough Idling and Tuning Challenges**

Reed valves can make the engine run rough at low RPMs if not properly tuned. This is due to the altered airflow dynamics, which may require adjusting the carburetor jets, ignition timing, or even switching to a different carburetor model. Some users report needing to experiment with tuning before achieving smooth operation.

3. **Cost of Additional Modifications**

While the V4R85A itself is priced reasonably (typically **$800 $1,200**), the supporting mods can add up quickly. A full build might require spending **$2,000 $4,000 **, depending on the level of upgrades. This can be a significant investment for riders on a budget.

4. **Limited Longevity Without Full Engine Support**

The V4R85A pushes the stock engine to its limits, which can accelerate wear on components like the crankshaft, connecting rods, and cylinder walls if not properly supported. Some users report increased oil consumption or piston ring wear over time, especially if the engine is not otherwise upgraded (e.g., with a stronger crank or forged internals).

5. **Not Ideal for Stock-Like Performance**

If your goal is to keep the bike as stock-like as possible for daily riding or legal compliance (e.g., avoiding insurance issues or emissions restrictions), the V4R85A is overkill. The power gains come at the expense of drivability and may void warranties or require registration changes in some regions.

6. **Learning Curve for Installation and Tuning**

While the installation is manageable for experienced DIYers, those without mechanical experience may struggle with tasks like carburetor tuning, ignition mapping, or ensuring proper reed valve alignment. Poor installation or tuning can lead to poor performance, engine damage, or even failure.

7. **Potential for Overbuilding the Engine**

Some riders may find that the V4R85A provides more power than they need, especially for street use. On a track, the extra power is valuable, but on the road, it can make the bike feel less refined or even dangerous if not properly controlled (e.g., with a limited-slip differential or upgraded brakes).

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### **Conclusion**

The **Moto Tassinari V-Force V4R85A** is one of the most effective and popular reed valve kits for KTM and Husqvarna air/oil-cooled engines. It delivers **substantial power gains** with relative ease of installation, making it a favorite among track-focused riders and those looking to significantly boost their bike s performance. However, it is not a "plug-and-play" solution it requires **careful planning, supporting modifications, and tuning** to avoid common pitfalls like rough idling, poor fueling, or premature engine wear.

For riders who are **mechanically inclined, willing to invest in additional upgrades, and prioritize performance over stock-like drivability**, the V4R85A is an excellent choice. It is particularly well-suited for **track use, aggressive riding, or projects where significant power increases are desired**. On the other hand, those seeking a **simple, budget-friendly upgrade** or those who want to maintain a stock-like experience should consider less invasive options (e.g., porting, camshaft upgrades, or a different reed valve kit like the **Moto Tassinari V-Force V2** for less aggressive gains).

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### **Recommendation**

- You are building a **track-focused or high-performance street bike** and are prepared to invest in supporting mods (carburetor, exhaust, fueling, clutch).

- You have **mechanical experience** or are willing to learn how to tune the engine properly.

- Your primary goal is **maximizing power** and you don t mind sacrificing some stock-like drivability.

- You own a **KTM or Husqvarna air/oil-cooled single-cylinder bike** (e.g., 450 SX-F, TE 450, or similar models) and want a reliable, high-quality reed valve kit.

- You want a **simple, low-cost upgrade** without major modifications.

- You are not comfortable with **carburetor tuning, ignition mapping, or mechanical work**.

- Your bike will primarily be used for **daily commuting or stock-like riding**.

- You are on a **tight budget**, as the total cost of a fully supported build will be significantly higher than the kit alone.

- You plan to **keep the bike legal for insurance or registration purposes** without modifications.

- **Moto Tassinari V-Force V2**: A less aggressive reed valve kit with moderate power gains, better suited for street use.

- **Porting and Polishing**: A more affordable way to improve airflow without reed valves.

- **Camshaft Upgrades**: Can provide noticeable power gains with fewer supporting mods.

- **EFI Conversion Kits**: If you re open to electronic fuel injection, brands like **Moto Tassinari s EFI systems** or **Walbro** offer more refined tuning options.

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**Final Verdict:** The V4R85A is a **top-tier choice for serious riders** looking to push their KTM or Husqvarna to its limits, but it demands commitment to supporting modifications and tuning. For those willing to put in the work, it is one of the best ways to unlock hidden power from these engines.

Details:

V-Force by Moto Tassinari 4R Reed Valve System #V4R85A KTM/Husqvarna: Long reed stops added to progressively slow petal tip velocity for increased durability. Pre-curved reed petal ensures better seal at the tip. Combined reed tip area is increased by 10.5% for better airflow. Wider reed cage for maximum airflow.

Made in the USA. Reduced frontal area of the central wing combined with a more aerodynamic shape. Airfoil shape added to cage tip increase velocity from outer ports. Replacement reeds sold one set per reed cage.

Advanced reed petal resin system, carbon fiber and lay-up.

part #: v4r85a prices

• $144.99-$179.99

specifications intakefuelmotorcycle:

• for makes: Ktm, Husqvarna
• brand: V-force
• mpn: V4r85a
• part type: Valve

general intakefuelmotorcycle:

• condition: New
• Motorcycle Scooter Parts Accessories > Air Intake Fuel Delivery > Other Air Intake Fuel Delivery

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• # reviews: 700007
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offer intakefuelmotorcycle:

• quantity: 2
• availability: In Stock
• options: Ship-to-home
• sold: 0
• started: April 12, 2026

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