NAMURA ORNA-RA421357-WX Piston Kit Bike 66.34MM

( Brand: Namura ), ( Manufacturer Part Number: ORNA-RA421357-WX ), ( Part Type: Piston )

Review NAMURA Honda Dirt Bike Piston Kit 66.34mm fits CR250 1986–1991

Introducing the Namura ORNA-RA421357-WX piston kit, specifically designed for Honda CR250 bikes manufactured between 1986 and 1991. This high-performance piston kit is an excellent choice for riders seeking to enhance their engine's power and efficiency.

The piston kit comprises of six individual pistons, each crafted from forged aluminum alloy. This material ensures superior strength and durability, allowing the pistons to withstand the rigors of high-performance riding. Each piston features a compression height of 39.5mm and a total height of 70.5mm, while the piston diameter measures 66.34mm.

The piston kit also includes piston rings made from heat-resistant, high-tensile steel. These rings are designed to maintain a tight seal within the engine cylinder, reducing the potential for combustion gases to escape. The kit includes two compression rings, one oil control ring, and one skirt oil scraper ring for each piston.

Moreover, the piston kit comes with piston pins made from chrome-molybdenum steel. These pins are designed to provide excellent strength and resistance to wear, ensuring a long-lasting and reliable fit within the crankshaft.

Installing the Namura ORNA-RA421357-WX piston kit is a straightforward process, making it an ideal upgrade for both amateur and professional mechanics. Each piston comes with its accompanying piston pin, making the assembly process more convenient. Additionally, the kit includes detailed instructions to help ensure a trouble-free installation.

In conclusion, the Namura ORNA-RA421357-WX piston kit is an excellent investment for Honda CR250 bike owners looking to improve engine performance and longevity. With its high-strength materials, precise measurements, and easy installation, this piston kit is an essential upgrade for any enthusiast seeking to maximize their riding experience.

Pros and Cons of Buying a Namura OR-A421357-WX Piston Kit for a 1986-1991 Honda CR250

a. Cost-effective: Replacing a piston with an aftermarket kit is generally more affordable than purchasing a new or OEM part.

b. Availability: Aftermarket piston kits like Namura's can be easier to find than OEM parts from Honda, especially for older models.

c. Performance potential: Some aftermarket piston kits may offer improved performance, such as increased power or better compression ratio.

a. Quality concerns: Aftermarket parts, including piston kits, may not meet the same quality standards as OEM parts. This could lead to premature failure or reduced performance.

b. Installation complexity: Installing aftermarket piston kits can be more challenging than OEM parts due to differences in size, shape, or other specifications.

c. Potential compatibility issues: Aftermarket piston kits may not be a perfect fit for your 1986-1991 Honda CR250, potentially leading to engine damage or reduced performance.

While the Namura OR-A421357-WX piston kit could save you money and potentially offer improved performance, it's crucial to consider the potential risks. Quality concerns, installation complexity, and compatibility issues are significant factors to weigh before deciding to purchase this aftermarket part. If you're confident in your mechanical abilities and willing to take the risk, the Namura piston kit could be a cost-effective solution. However, if you value the peace of mind that comes with OEM parts or prefer a hassle-free installation process, it might be worth considering alternative options.

If you're comfortable with the potential risks and the benefits of the Namura piston kit align with your goals, it could be worth pursuing. Before making a purchase, ensure you have a clear understanding of the installation process and compatibility requirements. Additionally, consider researching other aftermarket piston kit options and reading reviews from other users to make an informed decision. If you're unsure, it's always a good idea to consult with a professional mechanic for advice.

Details:

This is helpful if you are buying multiple items. Credit or Debit Card. Piston Size: 66.34mm. 1986 - 1991 Honda CR250 Dirt Bike Namura Piston Kit 66.34mm: Kit Contains: One piston, Matching Ring, Pin and Cir clips.

Compatibility: Honda CR250R 1986 - 1991. I need to exchange an item.: Brand: Namura, model Number: ORNA-RA421357-WX. Parts without fitment are to be assumed universal and may require vehicle modification.

part #: ornara421357 price

• $77.14

specifications pistondon:

• for models: Cr250
• for makes: Honda
• for years: 1986-1991
• brand: Namura
• mpn: Orna-ra421357-wx
• part type: Piston

general pistondon:

• condition: New
• Motorcycle Scooter Parts Accessories > Engines Engine Parts > Pistons, Rings Piston Kits

payments pistondon:

• other
• credit card: Diners-club
• wallet: Apple-pay

offer pistondon:

• options: Ship-to-home
• quantity: 5
• started: January 20, 2026
• availability: In Stock
• sold: 0

seller pistondon:

• rating: 99.8%
• city: San Marcos, CA
• # reviews: 75641

shipping pistondon:

• type: Fixed
• service: Standard
• class: Standard
• cost: $0.00
• transit: 3-7 Days

returns pistondon:

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

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