HONDA 04921-KSR-A00 Right Engine Crankcase 312

( Manufacturer Part Number: 04921-KSR-A00 ), ( Part Type: Engine Case ), ( Non-domestic Product: No ), ( Machine Type: Dirt Bike, Off-road Motorcycle ), ( Compatible Model: Cr125, Cr125r ), ( Material: Aluminum ), ( Placement On Vehicle: Right ), ( Compatible Year: 2007, 2006, 2005, 2004, 2003, 2002, 2001, 2000, 1999, 1998 ), ( Performance Part: Yes )

Review HONDA Right Side Engine Case Crankcase 312 fits CR125R 2004

The **Honda 04921-KSR-A00 (2004 CR125R Right Engine Crankcase, Part #312)** is a meticulously engineered, high-performance component designed specifically for Honda s iconic 2004 model year CR125R, a sporty and agile 125cc adventure bike renowned for its balance of off-road capability and on-road precision. This right-side engine crankcase is a critical part of the bike s powertrain, housing the crankshaft, connecting rods, and other essential drivetrain components while contributing to the overall rigidity and durability of the frame. Crafted from high-strength aluminum alloy, this crankcase is precision-machined to Honda s exacting standards, ensuring a seamless fit with the left crankcase and cylinder assembly, which guarantees optimal torque transfer and smooth operation. The design incorporates intricate internal passages and mounting points that align perfectly with the bike s suspension and transmission systems, allowing for efficient power delivery and minimal vibration during both high-speed cruising and rough-terrain riding. Whether you re restoring a classic CR125R to its factory glory or upgrading an existing bike for enhanced performance, this OEM replacement crankcase delivers the reliability and structural integrity expected from Honda s legendary engineering. Its compatibility with the 2004 model ensures that all mating surfaces, including the oil pump housing, clutch housing, and timing cover, align flawlessly, reducing the risk of leaks or misalignment that could compromise performance. For riders and mechanics seeking a direct, no-compromise solution, this crankcase is an essential part that upholds the CR125R s reputation for being a versatile, durable, and thrilling ride whether tackling dirt trails or navigating urban streets.

### **Pros and Cons of buying a Honda 04921-KSR-A00 (2004 CR125R Right Engine Crankcase, Part #312)**

1. **OEM Quality** This is a genuine Honda replacement part, ensuring compatibility and reliability. Honda s reputation for durability means the component will fit and function as intended without major modifications.

2. **Reliability** The CR125R is a well-built motorcycle, and Honda s engine components are known for longevity when properly maintained. The crankcase is a critical part, and a new one can restore performance if the original was damaged or worn.

3. **Ease of Installation** Since it s a direct replacement, installation should be straightforward for someone with basic mechanical skills. Honda s design consistency across models makes it easier to work with than aftermarket parts that may require adjustments.

4. **Resale Value** A motorcycle with original or high-quality replacement parts retains better resale value. If you plan to sell the bike later, using an OEM part like this helps maintain its condition.

5. **Warranty Coverage** If purchased from an authorized Honda dealer or a reputable seller, this part may come with a warranty, providing peace of mind against defects.

6. **Performance Restoration** If the original crankcase was cracked, leaking oil, or damaged, replacing it can restore the engine s efficiency and prevent further issues like bearing wear or oil starvation.

7. **Compatibility with Modifications** If you plan to modify the engine (e.g., porting, upgrading internals), a fresh crankcase provides a clean slate for such projects.

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1. **Cost** OEM Honda parts are more expensive than aftermarket alternatives. The price of this crankcase may be prohibitive for budget-conscious buyers, especially if the bike is not a high-value project.

2. **Limited Availability** While Honda parts are widely available, finding a specific part number (like this one) may require ordering from a dealer or online marketplace, which could involve shipping delays or higher costs.

3. **Potential for Counterfeit Parts** Buying from unauthorized sellers increases the risk of receiving a fake or low-quality part. Always verify the seller s reputation and authenticity of the part number.

4. **Labor Intensive Replacement** Replacing a crankcase requires disassembling the engine, which can be time-consuming and may require specialized tools (e.g., torque wrench, gasket scraper). If you lack mechanical experience, labor costs at a shop could add up.

5. **Age of the Part** While the part itself is new, the bike is from 2004, meaning other components (e.g., clutch, transmission, or frame) may be worn and need attention. Buying just the crankcase without addressing these could lead to recurring issues.

6. **No Significant Performance Gain** Unlike aftermarket parts (e.g., forged internals, high-flow exhaust), replacing the crankcase with an OEM part does not improve power or handling. It s primarily a repair or restoration component.

7. **Environmental and Ethical Considerations** If the original crankcase was removed due to damage (e.g., accident), purchasing a new one contributes to e-waste. Consider whether the bike s condition justifies the replacement or if it s better to part out the bike for spare parts.

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The **Honda 04921-KSR-A00 crankcase** is a sound investment if you need to **restore or repair** a 2004 CR125R engine that has suffered damage (e.g., oil leaks, cracks, or internal wear). Its **OEM quality, reliability, and compatibility** make it a trusted choice for serious riders or those restoring a classic bike. However, the **high cost, labor requirements, and potential for other hidden issues** in the bike mean it s not a "set-and-forget" upgrade.

If your primary goal is **performance or cosmetic enhancement**, this part alone won t deliver much. But if the engine s structural integrity is compromised, replacing the crankcase is a **practical and prudent fix** to avoid catastrophic failure.

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- You ve confirmed the crankcase is damaged (e.g., cracks, oil leaks, or internal corrosion).

- You re restoring the bike to original or near-original condition and want OEM reliability.

- You have the mechanical skills (or access to a mechanic) to install it properly.

- The bike s overall condition is good, and this is the only major engine component needing replacement.

- The bike has other severe issues (e.g., frame rust, transmission problems) that would require extensive work.

- You re on a tight budget and can find a cheaper alternative (e.g., a used but serviceable crankcase from a salvage yard).

- You re not committed to completing the repair leaving the bike half-fixed could lead to further damage.

- You re buying it purely for performance gains (consider aftermarket internals or a full rebuild instead).

- **Verify the part number and seller** to avoid counterfeits.

- **Check the bike s full condition** before committing don t just replace the crankcase without addressing other wear.

- **Budget for labor** if you re not doing the work yourself.

- **Consider alternatives** (e.g., used parts, rebuild kits) if cost is a major concern.

For most riders, this is a **worthwhile purchase for engine longevity**, but weigh the cost against the bike s overall value and your project goals.

Details:

The Ask a Question link near bottom left of this listing for quick response THIS LISTING IS PARTS PULLED FROM AN EXCELLENT RUNNING AND RIDING 2004 HONDA CR125R. No heavy wear - broken/missing parts or pieces cracks, repairs, breaks, bends, twists, etc stripped threads/bolts THESE PARTS FIT MANY YEARS OF HONDA CR125R AND CR250R MOTORCYCLES. 04921-KSR-A00 SAME DAY SHIPPING.

part #: 04921ksra00 prices

• $320.00-$399.99

specifications cyclevintagee:

• for makes: Honda
• mpn: 04921-ksr-a00
• part type: Engine Case
• non-domestic product: No
• machine type: Dirt Bike, Off-road Motorcycle
• compatible model: Cr125, Cr125r
• material: Aluminum
• placement on vehicle: Right
• compatible year: 2007, 2006, 2005, 2004, 2003, 2002, 2001, 2000, 1999, 1998
• performance part: Yes

returns cyclevintagee:

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

seller cyclevintagee:

• # reviews: 2106
• rating: 100.0%
• city: Hutchinson, Kansas

shipping cyclevintagee:

• carrier: UPS, FedEx
• transit: 4-6 Days
• type: Calculated
• cost: $10.63
• service: UPS Ground Saver, UPS Ground, FedEx Ground / FedEx Home Delivery, UPS 2nd Day Air
• class: Economy, Standard, Expedited

payments cyclevintagee:

• wallet: Paypal
• other
• credit card: Diners-club

general cyclevintagee:

• Parts Accessories > Motorcycle Scooter Parts Accessories > Other Motorcycle Scooter Parts Accessories
• condition: Used

offer cyclevintagee:

• started: May 28, 2026
• options: Ship-to-home
• quantity: 1
• availability: In Stock
• sold: 0

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