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Start ShoppingCometic C9258 - Premium Big Twin Engine Seal for Harley-Davidson Panhead/Shovelhead/Evo - High-Quality Gasket Replacement
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Description
Ensure peak engine performance with Cometic's C9258 seal, engineered for Harley-Davidson Big Twin engines. This critical component prevents leaks and maintains compression, keeping your classic bike running smoothly for years.
Key Features
- Model Compatibility: Precision-fit for Panhead, Shovelhead, and Evolution Big Twin engines.
- Material Quality: Durable rubber compound resists degradation from heat and oil.
- Sealing Precision: Factory-tolerance dimensions ensure a perfect seal against leaks.
- Long-Lasting Design: Built to withstand harsh riding conditions and frequent maintenance.
Why Choose This Product
Cometic's C9258 seal delivers unmatched reliability for vintage and modern Harley engines. Its exact specifications ensure a perfect fit, while premium materials prevent oil leaks and maintain compression. Riders trust Cometic for parts that match original equipment performance, making this seal essential for maintaining your bike's power and longevity.
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Ensure peak engine performance with Cometic's C9258 seal, engineered for Harley-Davidson Big Twin engines. This critical component prevents leaks and maintains compression, keeping your classic bike running smoothly for years.
Key Features
- Model Compatibility: Precision-fit for Panhead, Shovelhead, and Evolution Big Twin engines.
- Material Quality: Durable rubber compound resists degradation from heat and oil.
- Sealing Precision: Factory-tolerance dimensions ensure a perfect seal against leaks.
- Long-Lasting Design: Built to withstand harsh riding conditions and frequent maintenance.
Why Choose This Product
Cometic's C9258 seal delivers unmatched reliability for vintage and modern Harley engines. Its exact specifications ensure a perfect fit, while premium materials prevent oil leaks and maintain compression. Riders trust Cometic for parts that match original equipment performance, making this seal essential for maintaining your bike's power and longevity.
| SKU | GMD0CF2CD5 |
|---|---|
| MPN | C9258 |
| Brand | Cometic |
| Category | Gaskets/Seals |
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Featured Review
| Make | Model | Years |
|---|---|---|
| Harley-Davidson | Big Twin Panhead | 1948-1965 |
| Harley-Davidson | Big Twin Shovelhead | 1966-1984 |
| Harley-Davidson | Big Twin Evolution | 1984-1999 |
Frequently Asked Questions
It is described for Panhead, Shovelhead, and Evolution Big Twin models. Because model-years and specific locations vary, confirm by cross-referencing your OEM part number with Cometic’s catalog or a Harley parts fiche before ordering.
Many seals are installed dry on the outside diameter and lightly oiled on the inner lip. However, follow the Harley-Davidson service manual for your specific model; some applications may call for a thin film of non-hardening sealant on the outer circumference.
No. Engine and primary seals are designed as single-use parts. Always install a new seal once the old one has been removed.
C9258 is typically a single seal only. If you are servicing a primary or case area, check if you also need associated gaskets or o-rings and order those separately.
Cometic components are widely used in performance Harley builds, but verify the application and any special clearances or installation procedures with your engine builder or Cometic technical support for high-horsepower setups.
Installation Guide
Difficulty
Medium
Est. Time
1 hr 0 min
Tools Required
- Basic SAE hand tools (wrenches, sockets)
- Torque wrench
- Seal puller or small pry tool (for old seal removal)
- Soft mallet
- Seal driver or appropriately sized socket
- Solvent/degreaser and clean rags
Pro Tips
- Lightly oil the seal lip and shaft before installation to prevent dry start
- Use a proper seal driver or a socket that contacts only the outer metal shell of the seal
- Mark the old seal depth before removal and match that depth with the new seal
- Inspect the shaft or mating surface for grooves; if worn, consider a sleeve or replacement part
Common Mistakes to Avoid
- Driving the new seal in crooked and damaging the sealing lip
- Not cleaning the sealing surface thoroughly before installation
- Reusing damaged or grooved shafts that will prematurely wear the new seal
- Over-applying sealant where not specified, leading to contamination inside the engine/primary
Comparison vs Stock/OEM
Intended as a direct replacement for OEM Harley-Davidson Big Twin seals with equivalent dimensions.
Improvements
- Aftermarket Cometic gaskets and seals are often engineered to meet or exceed OEM specifications.
- Cometic is widely used in performance and racing applications, suggesting robust sealing reliability when correctly installed.
Considerations
- Always verify the exact OEM part number and location the seal supersedes; Cometic cross-reference is recommended.
- Performance builds or modified engines may have different requirements; consult an engine builder if unsure.
Durability & Warranty
Expected Lifespan
Comparable to OEM seal life when installed correctly and used with clean, correct-spec fluids.
Warranty
Standard Cometic warranty terms apply via the retailer or distributor; check point of purchase for specifics.
Maintenance
Periodically inspect for leaks during routine service. Replace if any weeping or contamination is observed around the seal area.
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