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  3. BOYESEN MN/37CV

BOYESEN MN-37CV Valve Boot Fuel Air Reed MN/37CV

fits model: Yz85. make: Yamaha. year: 2002–2020.

37cv Boyesen Mn/37cv Rad Valve Boot For 2002-2020 Yamaha Yz85 - Fuel And Air Reeds Reed Tx

( Brand: Boyesen ), ( Manufacturer Part Number: MN/37CV ), ( Compatible Year: 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 ), ( Bundle Description: 1 Pc Genuine Boyesen Rad Valve Boot ), ( Type: Rad Valve Boot ), ( Core Charge: Free No Core Charge ), ( Fitment Type: Direct Replacement )

Review BOYESEN Mn/37cv Rad Valve Boot Yamaha Fuel And Air Reeds Reed Tx fits YZ85 2002–2020

The Boyesen MN/37CV Rad Valve Boot is a meticulously engineered, high-performance replacement part designed specifically to restore and enhance the functionality of the fuel-air reed system on Yamaha YZ85 dirt bikes manufactured between 2002 and 2020. Crafted from durable, heat-resistant rubber with reinforced stitching, this valve boot is built to withstand the demanding conditions of off-road riding, ensuring a secure and reliable seal that prevents air leaks while maintaining optimal airflow into the engine s reed chamber. The boot features a snug, interference-fit design that snaps effortlessly into place over the reed assembly, eliminating the need for adhesives or excessive force, which could damage the delicate reed mechanism. Its precision-molded shape guarantees a perfect alignment with the bike s stock components, reducing the risk of misalignment or improper sealing that can lead to power loss, rough idle, or even reed damage over time. Ideal for riders seeking to maintain peak engine performance, this valve boot is a straightforward yet critical upgrade that helps preserve the integrity of the reed system, extending its lifespan and ensuring consistent throttle response under heavy loads. Whether addressing wear from age, replacing a damaged boot, or simply performing routine maintenance, the Boyesen MN/37CV Rad Valve Boot is a dependable, easy-to-install solution that keeps your YZ85 running smoothly and efficiently.

### Pros and Cons of Buying a Boyesen MN/37CV Rad Valve Boot for a 2002 2020 Yamaha YZ85 Fuel Air Reed System

#### **Pros:**

1. **Improved Performance** The Boyesen MN/37CV is designed to enhance airflow and exhaust efficiency, which can lead to better throttle response, increased horsepower, and smoother power delivery. For a YZ85, this can make the bike feel more responsive, especially in mid-range and high-RPM scenarios.

2. **Durability and Quality** Boyesen parts are known for their robust construction, often using high-quality materials like stainless steel and reinforced seals. This can extend the lifespan of the valve boot compared to OEM alternatives, reducing the risk of leaks or premature failure.

3. **Compatibility** The MN/37CV is specifically engineered for the Yamaha YZ85 s fuel air reed system, ensuring a proper fit without the need for extensive modifications. This reduces the risk of installation errors that could damage the engine.

4. **Easier Installation** Compared to some aftermarket exhaust systems or full reed kits, the valve boot is a relatively straightforward upgrade. It can often be installed in under an hour with basic tools, making it accessible for DIY enthusiasts.

5. **Cost-Effective Tuning** While not a cheap part, it offers a more affordable way to gain performance gains compared to full engine rebuilds or high-end exhaust systems. It s a targeted upgrade that addresses a specific bottleneck in the intake/exhaust flow.

6. **Potential for Further Tuning** Installing the Boyesen valve boot can allow for better tuning with other aftermarket parts (e.g., a high-flow air filter, upgraded carburetor, or ECU flash) since the engine will have improved breathing capacity.

7. **Reduced Backpressure** The design of the MN/37CV reduces exhaust backpressure, which can help the engine scavenge exhaust gases more efficiently, particularly beneficial for two-stroke engines like the YZ85 s.

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#### **Cons:**

1. **Limited Performance Gains** While noticeable, the improvements may not be dramatic enough for serious racers or those seeking extreme power. The YZ85 is already a lightweight, high-revving bike, and the valve boot upgrade is more of a refinement than a revolutionary change.

2. **Requires Additional Modifications** For optimal results, pairing the valve boot with other upgrades (e.g., a high-flow air filter, reed kit, or carburetor adjustment) may be necessary. Without these, gains could be modest.

3. **Potential for Voiding Warranty** If the bike is still under manufacturer warranty, installing aftermarket parts like the Boyesen valve boot could void coverage, especially if the dealer considers it a "performance modification."

4. **Installation Challenges** While easier than some upgrades, the valve boot is still a precision part. Improper installation (e.g., incorrect sealing or misalignment) could lead to leaks, reduced performance, or even engine damage. Careful attention to detail is required.

5. **Cost Relative to Benefit** At around $100 $150, the valve boot is not the cheapest upgrade. For casual riders, the gains may not justify the expense unless paired with other mods.

6. **Noise and Exhaust Flow Changes** Some riders report a slight increase in exhaust note, which may not be desirable for those who prefer a quieter, stock-like sound. Additionally, the exhaust flow changes could alter the bike s tuning characteristics.

7. **Not a Complete Solution** The valve boot addresses one aspect of the intake/exhaust system, but other bottlenecks (e.g., carburetor size, reed valves, or exhaust restrictions) may still limit performance. A holistic approach to tuning is often better.

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### **Conclusion:**

The Boyesen MN/37CV Rad Valve Boot is a worthwhile upgrade for Yamaha YZ85 owners who want to improve their bike s performance without a full rebuild. It offers tangible benefits in airflow, throttle response, and efficiency, particularly when combined with complementary mods. However, it is not a "magic bullet" and should be considered part of a broader tuning strategy rather than a standalone solution.

For **casual riders** or those on a budget, the gains may be modest, and the cost may not be justified unless paired with other upgrades. For **enthusiasts or racers**, it is a practical and effective step toward optimizing the YZ85 s power delivery, especially if the bike is already equipped with other performance parts.

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### **Recommendation:** - **Buy the Boyesen MN/37CV** if:

- You are already running or plan to run other performance parts (e.g., high-flow air filter, reed kit, or ECU tune).

- You notice the YZ85 s stock exhaust system is limiting power, particularly in the mid-to-high RPM range.

- You are comfortable with basic installation and tuning adjustments.

- You prioritize durability and a higher-quality part over the cheapest option.

- **Avoid or delay purchase if:**

- You are a casual rider who primarily uses the bike for light trail riding and doesn t plan further mods.

- You are concerned about warranty voiding or prefer to keep the bike stock.

- You expect dramatic power gains without additional upgrades expect incremental improvements.

- You are on a tight budget and can achieve similar (though less refined) results with cheaper alternatives (e.g., a high-flow air filter alone).

**Final Verdict:** The Boyesen MN/37CV is a solid, well-engineered upgrade for the YZ85 that delivers measurable performance benefits. It is best suited for riders who are actively tuning their bikes and want to address specific airflow restrictions. For those looking for a straightforward, high-quality part to enhance their YZ85 s capabilities, it is a recommended purchase.

Details:

Boyesen Rad Valve Boot for 2002 - 2020 Yamaha YZ85 - Fuel Air Reeds Reed tx: Status: In Stock.

part #: mn37cv price

  • $49.79

specifications intakefuelmotorcycle:

  • for models: Yz85
  • for makes: Yamaha
  • for years: 2002-2020
  • brand: Boyesen
  • mpn: Mn/37cv
  • compatible year: 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008
  • bundle description: 1 Pc Genuine Boyesen Rad Valve Boot
  • type: Rad Valve Boot
  • core charge: Free No Core Charge
  • fitment type: Direct Replacement

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offer intakefuelmotorcycle:

  • started: May 12, 2026
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  • Motorcycle Scooter Parts Accessories > Air Intake Fuel Delivery > Other Air Intake Fuel Delivery

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for models: yz85, for makes: yamaha, for years: 2002-2020, compatible year: 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008, bundle description: 1 pc genuine boyesen rad valve boot, type: rad valve boot, core charge: free no core charge, fitment type: direct replacement,
category: motorcycle parts > motorcycle scooter parts accessories > air intake fuel delivery, sku: 23828892315982813,
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