BFO KYZV3S Carburetor Carb Kit

( Brand: Bfo ), ( Manufacturer Part Number: KYZV3S ), ( Air Filter Mount Inner Diameter: 55mm ), ( Air Filter Mount Outer Diameter: 58mm ), ( Bundle Description: Carburetor For Polaris Base Cover Rubber Ring Filter Screws ), ( California Prop 65 Warning: California Prop 65 Warning ), ( Choke Type: Mechanical ), ( Custom Bundle: Yes ), ( Engine Type: 4-stroke ), ( Fitment Type: Direct Replacement ), ( Intake Side Inner Diameter: 40mm ), ( Intake Side Outer Diameter: 46mm ), ( Items Included: Gasket, Mounting Hardware, O-rings ), ( Machine Type: Atv ), ( Manufacturer Warranty: 2 Years ), ( Material: Alloy, Aluminum ), ( Mounting Flange Type: Bolt On ), ( Note: No Instruction Included ), ( Notice: This Is Aftermarket Replcement Part. ), ( Oe/oem Part Number: Carburetor, Carburettor, Carburetter, Carb, Carby ), ( Part Type: Carburetors Throttlebodies ), ( Quantity: 1 Piece As Show In The Picture ), ( Surface Finish: Brand New ), ( Type: Carburetor ), ( Universal Fitment: No ), ( Country Of Origin: China )

Review BFO Carburetor Carb Kit Polaris fits SCRAMBLER 400 4X4 500 1999–2007

The **BFO KYZV3S Carburetor & Carb Kit** is a meticulously engineered performance upgrade designed specifically for Polaris Scrambler 400 and 4x4 models from the years 1999 through 2007, including the 500cc variants. This high-quality kit replaces the stock carburetor with a precision-machined, high-flow **KYZV3S carburetor**, a model renowned for its reliability, smooth throttle response, and enhanced power delivery across the entire RPM range. Crafted from durable materials, including anodized aluminum for the body and heat-treated components for the internals, this carburetor is built to withstand the demands of aggressive riding while maintaining optimal fuel efficiency and emissions compliance. The kit includes a complete set of essential parts, such as the **fuel pump, throttle cable, and necessary gaskets**, ensuring a seamless installation process without the need for additional aftermarket components. The KYZV3S features a **variable venturi design**, which allows for better air-fuel mixture control, reducing hick-ups and improving throttle smoothness critical for off-road applications where quick, responsive power is essential. Whether you're tackling rough terrain, hitting the trail at high speeds, or simply seeking a more engaging ride, this carb kit delivers a noticeable boost in performance while preserving the stock engine s longevity. Backed by BFO s reputation for precision engineering and customer support, this upgrade is ideal for riders who demand both power and reliability from their Polaris Scrambler.

### **Pros and Cons of buying a BF0 KYZV3S Carburetor Kit for a Polaris Scrambler 400/4x4 (1999 2007)**

1. **Improved Performance** The KYZV3S carburetor is a high-performance upgrade designed to enhance throttle response, power delivery, and overall engine efficiency. It is optimized for modern fuel standards and can provide a noticeable boost in acceleration and top-end power compared to the stock carburetor.

2. **Better Fuel Economy (Under Certain Conditions)** When properly tuned, a well-maintained carburetor can improve fuel efficiency by ensuring optimal air-fuel mixture, especially if the original carburetor was running rich or inefficient.

3. **Compatibility with Modern Fuel** Unlike older carburetors that may struggle with modern gasoline blends (higher ethanol content), the KYZV3S is designed to work effectively with today s fuel, reducing the risk of clogging or poor performance.

4. **Aftermarket Support and Tuning Options** The KYZV3S is a popular carburetor in the Polaris community, meaning there are widely available tuning guides, jetting charts, and aftermarket parts (such as fuel pumps, air filters, and exhaust systems) to complement it.

5. **Durability and Reliability** Keihin carburetors are known for their robust construction and longevity, especially when maintained properly. The KYZV3S is no exception, offering a solid alternative to the stock carburetor, which can wear out over time.

6. **Easier Maintenance Than Some Alternatives** While carburetors require regular cleaning and adjustment, the KYZV3S is relatively straightforward to service compared to some other high-performance carburetors (e.g., Mikuni or Walbro models) that may require more specialized tools or expertise.

7. **Potential for Increased Reliability** If the original carburetor was leaking vacuum, flooding, or struggling with idle stability, upgrading to a KYZV3S can resolve these issues, leading to a more consistent and reliable engine.

8. **Resale Value and Enthusiast Appeal** A well-maintained Scrambler with a KYZV3S carburetor may appeal more to buyers looking for a performance-oriented bike, potentially increasing its resale value among enthusiasts.

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1. **Cost** The KYZV3S carburetor kit is more expensive than the stock carburetor, and installation may require additional parts (such as a new fuel pump, lines, and possibly a new air filter or exhaust system) to fully optimize performance. The total cost can range from **$200 $400 **, depending on whether you purchase a complete kit or individual components.

2. **Installation Complexity** While not extremely difficult, installing a new carburetor requires careful attention to vacuum lines, throttle linkage, and fuel system adjustments. If you re not comfortable with mechanical work, you may need to pay a mechanic, adding to the expense.

3. **Tuning Required** Simply swapping in the KYZV3S won t guarantee optimal performance. You ll need to adjust the jetting (main jets, pilot jets, and needle settings) based on fuel type, altitude, and riding conditions. Poor tuning can lead to **lean or rich mixtures**, causing rough idling, stalling, or reduced power.

4. **Potential for Flooding or Rough Idle** If the carburetor isn t properly broken in or if the fuel system isn t adjusted correctly, you may experience **flooding (excess fuel)** or a **rough idle**, especially during cold starts. This requires patience and fine-tuning.

5. **Ongoing Maintenance** Carburetors require regular cleaning (every 50 100 hours) to prevent gumming and clogging. Unlike fuel-injected systems, they are more prone to dirt and debris buildup, which can affect performance if neglected.

6. **Compatibility with Stock Components** While the KYZV3S fits the 1999 2007 Scrambler 400/4x4, some riders report that pairing it with stock components (e.g., the original air filter or exhaust) may not fully realize its potential. Upgrading the air intake or exhaust can further enhance performance but adds cost.

7. **Learning Curve for Beginners** If you re new to carbureted engines, the KYZV3S may feel overwhelming due to the need for adjustments. Many riders opt for a **carburetor tuning service** or **ECU flash** (if available) to simplify the process.

8. **Environmental and Emissions Concerns** In some regions, heavily modified carbureted engines may face scrutiny under emissions regulations, though this is less of an issue for off-road use.

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### **Conclusion and Recommendation**

The **BF0 KYZV3S carburetor kit is a solid upgrade for a 1999 2007 Polaris Scrambler 400/4x4**, offering noticeable performance gains, better reliability, and compatibility with modern fuel. However, it is not a "plug-and-play" solution it requires **proper installation, tuning, and maintenance** to avoid common pitfalls like flooding, rough idling, or reduced fuel economy.

#### **Who Should Buy It?**

- **Performance-oriented riders** who want a noticeable power increase and are willing to invest time in tuning.

- **Owners experiencing issues** with their stock carburetor (e.g., flooding, poor throttle response, or vacuum leaks).

- **Those who enjoy DIY mechanics** and are comfortable adjusting jetting and fuel systems.

- **Enthusiasts who plan to pair it with complementary upgrades** (e.g., high-flow air filter, exhaust, or fuel pump).

#### **Who Should Avoid It?**

- **Casual riders** who prioritize simplicity and don t want to deal with carburetor maintenance.

- **Those on a tight budget**, as the cost of the carburetor plus tuning and potential additional parts can add up.

- **Beginners unfamiliar with carbureted engines**, unless they are willing to learn or seek professional help.

- **Riders in high-altitude areas** without proper jetting adjustments, as this can lead to lean mixtures and engine damage.

If you re serious about improving your Scrambler s performance and willing to put in the effort to tune and maintain the carburetor, the **KYZV3S is an excellent choice**. However, if you prefer a more hands-off approach, consider alternatives like:

- **A carburetor tuning service** (if your stock carburetor is still functional but poorly tuned).

- **An ECU flash** (if available for your model year) to optimize stock components.

- **A different carburetor model** (e.g., a Mikuni or Walbro) if you prefer a different tuning curve.

For most enthusiasts, the **KYZV3S is a worthwhile investment** just be prepared for the learning curve and maintenance requirements. If installed and tuned correctly, it can transform your Scrambler into a more responsive and powerful off-road machine.

Details:

Specifications. Manufacturer. 1.Made of high quality zinc/aluminum alloy, add more horse power while maintaining near stock fuel mileage. PRODUCT DISPLAY Carburetor Carb Kit for Polaris Scrambler 400 4X4 1999 500 2007.

3.Low fuel consumption, start fast stable idle speed, allowing you to get a better driving experience and maneuverability. Materia:Aluminum Alloy, Vehicle Service Type:ATV, Choke Type:Manual choke, Barrel Count:1, Mounting Flange Type: Bolt On, Fuel Gasoline, Intake Side Inner Diameter: 40mm, Outer 46mm, Air Filter 55mm, 58mm. Package Content. 2.Mix air and gasoline in a correct ratio to ensure proper engine function, give your machine new power.

4.100% tested For reliability and performance, backed by satisfying after-sales service. Please follow our return. For Polaris Sportsman 500 4X4 HO 2001 -2005, RSE 2001, DUSE 2010 -2012. Quick, Simple.

To ensure correct purchase, please compare carburetor against picture before you purchase. Always the correct part. Please clean up the oil channels and air filters as well use fuel before installing carburetors. Guaranteed Fitment.

specifications carbthrotatv:

• for models: 400, 4x4, 500, Scrambler
• for makes: Polaris
• for years: 1999-2007
• brand: Bfo
• mpn: Kyzv3s
• air filter mount inner diameter: 55mm
• air filter mount outer diameter: 58mm
• bundle description: Carburetor For Polaris Base Cover Rubber Ring Filter Screws
• california prop 65 warning: California Prop 65 Warning
• choke type: Mechanical
• custom bundle: Yes
• engine type: 4-stroke
• fitment type: Direct Replacement
• intake side inner diameter: 40mm
• intake side outer diameter: 46mm
• items included: Gasket, Mounting Hardware, O-rings
• machine type: Atv
• manufacturer warranty: 2 Years
• material: Alloy, Aluminum
• mounting flange type: Bolt On
• note: No Instruction Included
• notice: This Is Aftermarket Replcement Part.
• oe/oem part number: Carburetor, Carburettor, Carburetter, Carb, Carby
• part type: Carburetors Throttlebodies
• quantity: 1 Piece As Show In The Picture
• surface finish: Brand New
• type: Carburetor
• universal fitment: No
• country of origin: China

offer carbthrotatv:

• started: June 4, 2026
• options: Ship-to-home
• best offers: True
• sold: 0
• quantity: 4
• availability: In Stock

seller carbthrotatv:

• city: Houston, Texas
• rating: 99.7%
• # reviews: 2171

payments carbthrotatv:

• wallet: Google-pay
• credit card: Mastercard
• other

shipping carbthrotatv:

• service: FedEx Ground / FedEx Home Delivery
• cost: $0.00
• transit: 2-5 Days
• type: Fixed
• carrier: FedEx
• class: Standard

general carbthrotatv:

• ATV, Side-by-Side UTV Parts Accessories > Air Intake Fuel Delivery > Carburetors
• condition: New

returns carbthrotatv:

• paid by: Seller
• time: 30 Days
• policy: Returns Accepted

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