HONDA 90021-KS7-000 Exhaust Valve Sealing Bolt

( Manufacturer Part Number: 90021-KS7-000 ), ( Part Type: Valve Exhaust Sealing Bolt ), ( Country Of Origin: Japan )

Review HONDA Exhaust Valve Sealing Bolt fits CR125R 125R CR 125 1986–1989

The **Honda 90021-KS7-000** is a precision-engineered exhaust valve sealing bolt designed specifically for the **1986-1989 Honda CR125R (and CR125R variants)**, ensuring optimal performance, reliability, and longevity for this iconic off-road motorcycle. Crafted from high-grade, heat-resistant steel, this bolt is engineered to withstand the extreme thermal and mechanical stresses encountered during high-performance riding, particularly in demanding trail, motocross, or enduro conditions. Its **torque-tightening specification** is meticulously calibrated to prevent loosening under vibration while avoiding overtightening, which could compromise the integrity of the cylinder head or exhaust valve mechanism. The bolt features a **smooth, corrosion-resistant finish**, protecting it from the harsh elements encountered in off-road environments, including moisture, dust, and chemical exposure, which can accelerate wear and failure in substandard components. Ideal for both restoration projects and routine maintenance, this bolt is a direct OEM replacement, ensuring an exact fit with the original CR125R s engine bay, including the **exhaust valve cover assembly**. Whether you're a seasoned mechanic performing a full rebuild or a rider addressing a minor but critical failure, this bolt guarantees a secure, leak-free seal, preserving compression and engine efficiency. Its compatibility extends seamlessly with aftermarket valve kits and performance upgrades, making it a versatile choice for riders looking to enhance their CR125R s reliability without sacrificing stock specifications. Proper installation requires the use of a torque wrench to adhere to Honda s recommended specifications, ensuring long-term durability and preventing premature wear on adjacent components.

### Pros and Cons of Buying a 1986-1989 Honda CR125R (Part Number: 90021-KS7-000 Exhaust Valve Sealing Bolt)

1. **Classic Reliability** Honda s CR125R from the late 1980s is known for its durable and straightforward engine design. With proper maintenance, these bikes often last well beyond their original lifespan, making them a cost-effective choice for riders who appreciate simplicity.

2. **Lightweight and Maneuverable** The CR125R is a small, agile bike, ideal for urban commuting, trail riding, or off-road adventures. Its compact size makes it easy to handle, park, and transport.

3. **Low Cost of Ownership** Parts for this model are widely available and inexpensive compared to modern bikes. Basic maintenance (oil changes, chain adjustments, etc.) is straightforward and doesn t require specialized tools or expertise.

4. **Fuel Efficiency** The 125cc single-cylinder engine is efficient, delivering good mileage (around 100 km/l under normal riding conditions). This makes it a practical choice for daily use or short trips.

5. **Minimalist Maintenance Needs** Unlike modern bikes with complex electronics or advanced suspension systems, the CR125R requires only basic upkeep. The engine is air-cooled, reducing the need for cooling system checks.

6. **Vintage Appeal** For enthusiasts who enjoy the nostalgia of classic motorcycles, the CR125R offers a simple, no-frills riding experience. Its retro design and straightforward operation can be appealing to riders who prefer a hands-on approach.

7. **Easy to Modify** The bike s simplicity allows for easy customization. Riders can upgrade components like the exhaust, handlebars, or suspension without major technical hurdles.

8. **Resale Value (for Well-Maintained Units)** While not a high-value bike, a clean and well-documented CR125R can still fetch a decent price in the used market, especially if it has a complete service history.

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1. **Age-Related Wear and Tear** As a bike from the late 1980s, the CR125R may require attention to common issues like worn-out belts, seals, or bearings. The **exhaust valve sealing bolt (part number 90021-KS7-000)** is a critical component, and if it s failing or worn, it could lead to exhaust leaks or reduced performance. Replacing it is a good idea if the bolt shows signs of corrosion or damage.

2. **Limited Power and Performance** The 125cc engine produces minimal power (around 10-12 horsepower), making it underpowered for highway speeds or aggressive riding. It s best suited for casual riding, not high-speed or sporty use.

3. **Basic Comfort and Ergonomics** The riding position is upright and relaxed, which is comfortable for short rides but can become fatiguing on longer trips. The bike lacks modern ergonomic features like adjustable seats or windshields.

4. **No Modern Safety Features** Unlike contemporary bikes, the CR125R lacks ABS, traction control, or advanced braking systems. Riders must rely on their own skill to handle the bike safely, especially in wet or slippery conditions.

5. **Fuel Injection vs. Carburetion** While some later models may have fuel injection, many CR125Rs from this era use carburetors, which can be finicky and require tuning over time. Fuel injection (if present) may offer better reliability but could also be more complex to diagnose if issues arise.

6. **Limited Aftermarket Support** While parts are available, the aftermarket for this specific model is not as extensive as for more modern or popular bikes. Finding rare or specialized components may require extra effort.

7. **Environmental Regulations** Depending on your location, older bikes may face restrictions on emissions or noise levels. Some regions require modifications to meet modern standards, which can be costly or impractical.

8. **Potential for Hidden Issues** Without a thorough inspection, buyers may inherit problems like a leaking head gasket, worn clutch, or damaged frame. Always test-ride the bike and check for signs of past neglect (e.g., rust, uneven tire wear).

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The **1986-1989 Honda CR125R** is an excellent choice for riders who prioritize simplicity, affordability, and low maintenance over modern performance and comfort. It s ideal for casual riders, commuters, or those who enjoy the charm of a classic bike. However, buyers should be prepared for potential age-related issues, particularly with critical components like the **exhaust valve sealing bolt**, and should budget for occasional repairs.

If you re buying this bike, **prioritize a thorough inspection** especially of the engine, exhaust system, and frame to avoid costly surprises. Replacing the **exhaust valve sealing bolt (90021-KS7-000)** if it s worn is a wise investment to prevent leaks and ensure proper sealing.

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- **Buy if:** You want a no-frills, reliable bike for casual riding, commuting, or off-road use; you re comfortable with basic maintenance; and you appreciate the simplicity of a classic design.

- **Avoid if:** You need a high-performance bike, modern safety features, or plan to ride at high speeds frequently. Also, avoid if the bike has a history of neglect or if the exhaust system (including the bolt) shows significant wear.

**Final Tip:** Always negotiate the price based on the bike s condition, mileage, and service history. A well-maintained CR125R can be a rewarding and cost-effective ride for years to come.

Details:

The condition of this item is displayed in the pictures above. For sale is the exhaust valve sealing bolt that was removed from a 1987 Honda CR125R. I do my best to describe the condition of parts in and pictures.

part #: 90021ks7000 prices

• $10.89-$45.00

specifications valvemotorcycleaz:

• for models: Cr125r, 125r, Cr, 125
• for makes: Honda
• for years: 1986-1989
• mpn: 90021-ks7-000
• part type: Valve Exhaust Sealing Bolt
• country of origin: Japan

seller valvemotorcycleaz:

• rating: 100.0%
• city: Lynchburg, Ohio
• # reviews: 1995

offer valvemotorcycleaz:

• sold: 0
• options: Ship-to-home
• availability: In Stock
• quantity: 1
• started: March 12, 2026

shipping valvemotorcycleaz:

• cost: $5.45
• class: Standard
• carrier: USPS
• type: Fixed
• transit: 4-9 Days
• service: USPS Ground Advantage

returns valvemotorcycleaz:

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

payments valvemotorcycleaz:

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

general valvemotorcycleaz:

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

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