YAMAHA 90508-80403-00 Rear Torsion Spring 90508-80403. Spring. 79-80

( Part Type: Spring ), ( UPC: 905088040300 )

Review YAMAHA 90508-80403. Oem Rear Torsion Spring. 79-80 fits EC540

The **Yamaha 90508-80403-00 Rear Torsion Spring** is a meticulously engineered component designed exclusively for the **EC540** model, manufactured between the years **1979 and 1980**. This spring is a critical part of the motorcycle s rear suspension system, ensuring smooth, controlled, and responsive handling while maintaining stability under varying loads and road conditions. Crafted from high-grade, durable steel, the torsion spring is precision-wound to deliver consistent torque and flexibility, allowing the suspension to absorb bumps, uneven terrain, and abrupt maneuvers with minimal effort. Its robust construction prevents premature fatigue, elongation, or breakage, which are common issues with lower-quality aftermarket replacements. The spring s design is optimized for the EC540 s specific suspension geometry, providing the ideal balance between firmness and compliance to enhance rider comfort and control. Whether navigating tight corners, cruising on highways, or tackling off-road trails, this genuine Yamaha part ensures that the rear suspension operates at peak performance, reducing wear on other drivetrain components and extending the longevity of the motorcycle s overall suspension system. For riders seeking reliability, authenticity, and the unmistakable feel of a Yamaha-built component, this rear torsion spring is an essential upgrade or replacement part that restores the original factory specifications and performance characteristics of the EC540.

### **Pros and Cons of buying a Yamaha 90508-80403-00 Rear Torsion Spring (EC540, 79-80 Model)**

1. **Authentic Fitment** This part is designed specifically for the **Yamaha EC540** from **1979-1980**, ensuring a perfect match with no modifications required. It eliminates the risk of compatibility issues that generic or aftermarket parts might introduce.

2. **Reliability and Durability** Yamaha s original torsion springs are built to last, using high-quality materials that resist wear and fatigue over time. This reduces the likelihood of sudden failure, which can be dangerous on a motorcycle.

3. **Safety** The rear suspension plays a critical role in handling and stability. A worn or broken torsion spring can lead to poor weight transfer, reduced control, and even accidents. Replacing it with an OEM part ensures the suspension functions as intended.

4. **Preservation of Value** If you plan to keep or sell the EC540 later, using genuine Yamaha parts helps maintain the bike s original condition and resale value. Aftermarket parts, even if they fit, may not hold the same appeal to collectors or serious buyers.

5. **Ease of Installation** Since this is an OEM part, it should align perfectly with the existing suspension components, making installation straightforward for someone with basic mechanical skills. Detailed instructions and tools (like a spring compressor) are typically required, but the process is well-documented for Yamaha models.

6. **Long-Term Cost Savings** While the upfront cost may be higher than some aftermarket alternatives, a genuine torsion spring is less likely to fail prematurely, saving you from repeated replacements or unexpected repairs.

7. **Sound and Feel** The original suspension tuning contributes to the EC540 s characteristic ride quality. Replacing with an aftermarket spring that alters the spring rate could change the bike s handling in ways that may not be desirable.

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1. **Higher Cost** Genuine Yamaha parts are typically more expensive than aftermarket alternatives. The price reflects the brand s reputation, quality, and the cost of sourcing original components. For some buyers, this may be a significant investment, especially if the spring is still functional but slightly worn.

2. **Limited Availability** Original Yamaha parts, particularly for older models like the EC540, can be harder to find than newer or more common parts. You may need to order from specialty motorcycle parts suppliers, which could involve longer wait times or shipping costs.

3. **Potential Overkill** If the torsion spring is only slightly worn and the suspension still functions adequately, replacing it may be unnecessary. In such cases, the cost may not be justified unless you re addressing a specific issue (e.g., a broken spring or excessive sag).

4. **Installation Complexity** While not extremely difficult, replacing a torsion spring requires careful handling to avoid damaging the spring or surrounding components. Mistakes during installation (e.g., improper torque on bolts or misalignment) can lead to premature wear or failure. If you re not comfortable with suspension work, you may need to pay a mechanic, adding to the cost.

5. **No Performance Upgrade** This is not a performance part; it s a replacement for a worn component. If you re looking to modify the suspension for better handling or comfort, you ll need to explore aftermarket options (e.g., stiffer or softer springs), which may not be compatible with the OEM part.

6. **Environmental and Ethical Considerations** Purchasing a new OEM part contributes to e-waste and resource consumption. If you re environmentally conscious, you might consider a used or refurbished part instead, though this carries its own risks (e.g., unknown wear history).

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- The spring is **broken, severely worn, or causing handling issues** and needs immediate replacement.

- You **prioritize authenticity, reliability, and long-term safety** over cost savings.

- You plan to **preserve the bike s original condition** for future use or resale.

- You re **comfortable with installation** or have access to a mechanic for the job.

- The spring is **only mildly worn** and the suspension still works fine, making the replacement unnecessary.

- You re on a **tight budget** and can find a **high-quality aftermarket alternative** that fits your needs.

- You re **not confident** in performing the installation yourself and don t want to pay for professional labor.

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1. **Assess the Condition of the Spring** Before purchasing, inspect the existing torsion spring for cracks, excessive sag, or rust. If it s still functional but slightly worn, consider monitoring it further or exploring aftermarket options.

2. **Compare Prices** Check multiple suppliers (eBay, Yamaha dealers, specialty parts stores) to ensure you re getting a fair price. Sometimes, used or refurbished OEM parts can be found at a discount.

3. **Consider Aftermarket Alternatives** If you re open to modifications, brands like **Progressive Parts, YSS, or Ohlins** offer torsion springs for the EC540 that may provide better performance or comfort at a lower cost. However, verify compatibility and reviews before purchasing.

4. **Budget for Installation** If you re not experienced with suspension work, factor in the cost of a mechanic ( $50 $100 depending on location). Some shops may offer discounts for OEM parts.

5. **Buy from a Reputable Source** Ensure the part is **genuine Yamaha** and not a counterfeit. Look for sellers with good reviews and clear product descriptions. If possible, purchase directly from Yamaha or an authorized dealer to avoid fakes.

6. **Document the Process** If you re installing it yourself, follow Yamaha s service manual or reputable online guides (e.g., from **Yamaha EC540 forums** or **Motorcycle Suspension Repair** resources). Take your time to avoid mistakes.

**Final Verdict:** If the spring is **failing or you want to maintain the bike s original integrity**, the **Yamaha 90508-80403-00 torsion spring is the safest and most reliable choice**. However, if you re looking for a **cost-effective or performance-focused alternative**, research aftermarket options carefully before deciding. Always prioritize safety and compatibility over convenience.

Details:

Feel free to ask questions. Fits Yamaha EC540 79-80. Please research part number for specifications to ensure this will work your vehicles make, model and year. Some NOS parts show normal shelf wear from age.

Yamaha 90508-80403. Years and model's stated are given as a range may or not include all years within. OEM Rear Torsion Spring.

part #: 905088040300 prices

• $14.95-$36.66

specifications snowmobileshocksoi:

• for models: Ec540
• for makes: Yamaha
• part type: Spring
• upc: 905088040300

offer snowmobileshocksoi:

• options: Ship-to-home
• sold: 0
• quantity: 2
• availability: In Stock
• started: June 8, 2026

payments snowmobileshocksoi:

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

general snowmobileshocksoi:

• Parts Accessories > Snowmobile Parts > Shocks Suspension
• condition: New other see details

seller snowmobileshocksoi:

• # reviews: 54233
• rating: 99.9%
• city: Townsend,

returns snowmobileshocksoi:

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

shipping snowmobileshocksoi:

• carrier: USPS
• transit: 4-10 Days
• cost: $11.35
• service: USPS Ground Advantage
• type: Calculated
• class: Standard

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