KAWASAKI RAD-12C Boyesen Reed Valve Intake Cage 12021-1109

( Manufacturer Part Number: RAD-12C ), ( Part Type: Valve Intake Cage ), ( Oe/oem Part Number: 12021-1109 )

Review KAWASAKI Boyesen Reed Valve Assembly Petal Intake Cage fits KX250 1994–1998

The **Kawasaki Rad-12C (1994-1998) 94-98 KX250 Boyesen Reed Valve Intake Cage (Part #12021-1109)** is a meticulously engineered aftermarket component designed to enhance the performance of Kawasaki s legendary 250cc trail bike, the KX250. Originally produced by Boyesen, a trusted name in motorcycle tuning, this intake cage is a direct replacement for the stock unit, ensuring a seamless fit while delivering measurable gains in airflow and throttle response. The Rad-12C designation indicates its compatibility with the KX250 s 12-valve engine configuration, which was a hallmark of Kawasaki s mid- 90s trail bike lineup, known for its balance of off-road capability and on-road versatility. Crafted from high-quality materials, the intake cage features a robust aluminum construction that not only reduces weight but also improves durability, allowing it to withstand the rigors of aggressive riding and frequent disassembly for maintenance. The cage s primary function is to house the reed valves, which regulate airflow into the engine by opening only when sufficient vacuum is present, preventing backpressure and improving power delivery especially at higher RPMs. This design is particularly beneficial for riders pushing the KX250 s limits, whether on technical trails or in competitive racing scenarios. The Boyesen intake cage is engineered to optimize the engine s breathing, resulting in a more responsive and efficient powerband, particularly noticeable in the mid-to-high RPM range. Installing this component is a straightforward process, requiring only basic tools and a bit of patience, as it involves removing the stock intake and securing the new cage in its place, often accompanied by the installation of a matching Boyesen throttle body for a complete performance upgrade. Beyond its performance benefits, the intake cage also offers a subtle aesthetic improvement, with its clean, angular design complementing the KX250 s sporty yet rugged appearance. Whether used as part of a full tuning project or as a standalone modification, this intake cage is a proven choice for enthusiasts looking to coax extra power and refinement from their Kawasaki Rad-12C, ensuring that the bike remains as capable and exciting as it was when it first rolled off the assembly line.

### **Pros and Cons of Buying a 1994 1998 Kawasaki Rad-12C (KX250-Based) with Boyesen Reed Valve Intake Cage (Part #12021-1109)**

#### **Pros**

1. **Unique and Rare Modification** The Boyesen reed valve intake cage is a highly sought-after aftermarket upgrade for the Rad-12C, significantly improving airflow and throttle response. This makes the bike stand out in the classic dirt bike market.

2. **Improved Performance** The reed valve system enhances breathing, especially at higher RPMs, making the bike feel more aggressive and responsive. This is particularly noticeable in the stock 250cc single-cylinder engine, which benefits from better airflow.

3. **Classic Rad-12C Appeal** The Rad-12C is already a cult favorite among off-road enthusiasts due to its lightweight, nimble handling, and retro styling. The Boyesen upgrade adds a performance edge while preserving the bike s vintage charm.

4. **Modular Upgrade Potential** The Boyesen kit is designed to work with the stock engine, but it opens the door for further modifications, such as porting the cylinder head, upgrading the exhaust, or installing a high-performance clutch.

5. **Good for Track and Trail** The improved throttle response makes the bike more suitable for track use, while the lightweight frame still allows for agile trail riding. This versatility is appealing to riders who want a bike that can handle both disciplines.

6. **Community and Customization** The Rad-12C has a dedicated following, and the Boyesen upgrade is a well-documented modification. This means you ll find plenty of resources, parts, and fellow enthusiasts to help with maintenance and tuning.

7. **Affordable Performance Boost** Compared to full engine swaps or major overhauls, the Boyesen kit is a relatively inexpensive way to significantly improve power delivery without sacrificing the bike s original character.

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#### **Cons**

1. **Stock Engine Limitations** While the Boyesen kit helps, the original 250cc single-cylinder engine is still limited in power compared to modern bikes. Expect strong mid-range torque but don t anticipate high-end horsepower. This may not satisfy riders looking for extreme performance.

2. **Maintenance and Reliability Concerns** Older Kawasaki engines, especially those from the mid-'90s, can be prone to wear if not properly maintained. The reed valve system adds complexity, and improper installation or lack of upkeep could lead to issues like valve float or intake leaks.

3. **Weight and Handling Trade-offs** The Boyesen kit adds some weight to the intake system, which may slightly offset the bike s lightweight feel. However, this is usually negligible compared to the performance gains.

4. **Availability of Parts** While the Boyesen kit itself is widely available, finding original Kawasaki parts for a 1994 1998 Rad-12C can be challenging. You may need to source aftermarket or used components for routine maintenance.

5. **Learning Curve for Modifications** If you re not experienced with dirt bike tuning, installing the Boyesen kit or further modifications may require patience and research. Improper installation could lead to poor performance or damage.

6. **Resale Value** Modified bikes, especially those with aftermarket parts like the Boyesen kit, typically have lower resale value than stock examples. If you plan to sell later, this could be a drawback.

7. **Noise and Legality** The improved airflow and exhaust potential (if modified further) may result in louder operation, which could violate noise ordinances in some areas. Check local regulations before making significant changes.

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### **Conclusion**

The **1994 1998 Kawasaki Rad-12C with a Boyesen reed valve intake cage** is an excellent choice for riders who appreciate classic dirt bikes and want a meaningful performance upgrade without a full engine rebuild. The Boyesen kit delivers noticeable improvements in throttle response and mid-range power, making the bike more enjoyable for both trail and track use. However, it s important to manage expectations this is not a high-performance machine but rather a fun, nimble bike with enhanced character.

If you re an enthusiast who values customization, community, and a balance of vintage charm with modern upgrades, this bike is a strong contender. Just be prepared for maintenance, potential part shortages, and the fact that it won t match the power of modern bikes. For riders who prioritize raw performance over nostalgia, a more heavily modified or modern bike might be a better fit.

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### **Recommendation**

- You love the Rad-12C s retro aesthetic and want to enhance its performance with a proven aftermarket upgrade.

- You re willing to invest time in maintenance and tuning to keep the bike running smoothly.

- You plan to use it for trail riding, light track days, or as a fun project bike.

- You re part of or willing to join the Rad-12C community for support and parts.

- You re looking for a high-performance dirt bike with modern power levels.

- You dislike maintenance or don t have access to mechanical skills/tools.

- You need a bike that will hold its value well for resale.

- You re in an area with strict noise regulations that may conflict with modified intake/exhaust setups.

**Final Verdict:** This is a fantastic bike for the right rider one who appreciates the blend of classic design and practical performance upgrades. With proper care, it can provide years of enjoyable riding. Just go in with realistic expectations about its capabilities and limitations.

Details:

Petals look great, have no gaps. I will do my best to resolve the issue. This is a nice looking and great working reed valve assembly. 1994 Kawasaki KX250.

Boyesen reed valve assembly. Incredible Deal on Genuine Parts. Reed valve assembly has no cracks, bends, welds, repairs, cut, etc. Boyesen Reed valve assembly will fit 1989 1998 KX250, 1991 - 1994 KDX250.

Please refer to the part number 12021-1109 for fitment. This is a good working item that has been used and perfect usable condition.

part #: rad12c prices

• $179.95-$188.95

specifications valvemotorcycleaz:

• for models: Kx250
• for makes: Kawasaki
• for years: 1994-1998
• mpn: Rad-12c
• part type: Valve Intake Cage
• oe/oem part number: 12021-1109

offer valvemotorcycleaz:

• quantity: 1
• sold: 0
• options: Ship-to-home
• started: May 23, 2026
• availability: In Stock

shipping valvemotorcycleaz:

• cost: $12.00
• service: USPS Priority Mail
• transit: 4-6 Days
• carrier: USPS
• class: Expedited
• type: Fixed

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• wallet: Apple-pay
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• other

general valvemotorcycleaz:

• condition: Used
• Engines Engine Parts > Valvetrain Components > Engine Valves

seller valvemotorcycleaz:

• # reviews: 9266
• rating: 99.8%
• city: Portland, Oregon

returns valvemotorcycleaz:

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

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