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Start ShoppingCometic C9150 Evo Big Twin Primary Housing Gasket - Reusable AFM Gasket for Harley Engines
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Description
Upgrade your Harley Big Twin's engine reliability with Cometic's C9150 primary housing gasket. This advanced AFM/fiber composite gasket delivers superior sealing performance while maintaining reusability, making it a trusted choice for riders demanding precision and durability.
Key Features
- AFM/Fiber Composite Material: Combines aluminum foam with fiber for exceptional heat resistance and sealing integrity under high-performance conditions.
- Reusable Design: Non-paper construction allows for multiple reuses without compromising seal effectiveness, reducing long-term costs.
- Harley-Specific Fit: Engineered to match the exact contours of Big Twin primary covers for a perfect, leak-free seal.
- Green Color Coding: Easy-to-identify color ensures proper gasket selection and prevents installation errors.
- USA Manufacturing: Made in the USA with strict quality control for reliable performance and durability.
- Individual Packaging: Sold separately for convenient storage and precise installation.
Why Choose This Product
Cometic's C9150 gasket is engineered for riders who prioritize engine longevity and performance. Its reusable design cuts replacement costs, while the AFM material withstands extreme temperatures and pressures. The precise fit for Harley Big Twin engines ensures optimal sealing, preventing oil leaks and maintaining engine efficiency. As a USA-made product, it meets rigorous quality standards for reliability on the road.
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Upgrade your Harley Big Twin's engine reliability with Cometic's C9150 primary housing gasket. This advanced AFM/fiber composite gasket delivers superior sealing performance while maintaining reusability, making it a trusted choice for riders demanding precision and durability.
Key Features
- AFM/Fiber Composite Material: Combines aluminum foam with fiber for exceptional heat resistance and sealing integrity under high-performance conditions.
- Reusable Design: Non-paper construction allows for multiple reuses without compromising seal effectiveness, reducing long-term costs.
- Harley-Specific Fit: Engineered to match the exact contours of Big Twin primary covers for a perfect, leak-free seal.
- Green Color Coding: Easy-to-identify color ensures proper gasket selection and prevents installation errors.
- USA Manufacturing: Made in the USA with strict quality control for reliable performance and durability.
- Individual Packaging: Sold separately for convenient storage and precise installation.
Why Choose This Product
Cometic's C9150 gasket is engineered for riders who prioritize engine longevity and performance. Its reusable design cuts replacement costs, while the AFM material withstands extreme temperatures and pressures. The precise fit for Harley Big Twin engines ensures optimal sealing, preventing oil leaks and maintaining engine efficiency. As a USA-made product, it meets rigorous quality standards for reliability on the road.| SKU | GM3E3A2166 |
|---|---|
| MPN | C9150 |
| UPC/GTIN | 191070019334 |
| Brand | Cometic |
| Category | Gaskets/Seals |
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Featured Review
| Make | Model | Years |
|---|---|---|
| Harley-Davidson | Big Twin (Evo & Twin Cam) | 1989-2006 |
Frequently Asked Questions
C9150 fits most 5‑speed Evo and Twin Cam Big Twin models from roughly 1989–2006. It does not fit 6‑speed Cruise Drive primaries (2006 Dyna, 2007‑up Touring/Softail). Always verify against your OEM primary cover gasket part and a retailer’s fitment chart.
No. Cometic’s AFM/fiber primary gaskets are designed to be installed dry on clean, flat mating surfaces. Using RTV or extra sealant can actually cause leaks or misalignment.
Cometic AFM gaskets are more tolerant of disassembly than paper gaskets and can sometimes be reused if undamaged, but for best sealing and to avoid labor repeat, most shops still recommend replacement whenever the primary is removed.
No. C9150 is the main outer primary housing gasket only. Derby, inspection cover gaskets, and drain plug o‑rings are sold separately or in complete primary gasket kits.
It is designed around stock‑style Harley Big Twin primary covers. Many aftermarket covers that retain stock gasket geometry will work, but you should confirm with the cover manufacturer.
Installation Guide
Difficulty
Medium
Est. Time
1 hr 0 min
Tools Required
- Harley primary drain plug tool or appropriate hex/Allen
- Socket set (SAE) and ratchet
- Torque wrench (inch‑lb and ft‑lb range for primary and derby screws)
- Primary cover gasket scraper or plastic razor scraper
- Brake cleaner or gasket surface cleaner
- Oil drain pan
- Shop rags
Pro Tips
- Test‑fit the gasket dry on the cover first so you know its orientation before applying it to the bike.
- Clean mating surfaces with a non‑residue brake cleaner and let them dry fully before installing the gasket.
- Install all primary cover screws finger‑tight first, then torque in a crisscross pattern to factory spec.
- Do not use silicone RTV on AFM‑style Cometic gaskets; they are designed to seal dry on proper surfaces.
- Inspect and, if needed, replace derby cover o‑ring and inspection cover gaskets while the primary is open.
Common Mistakes to Avoid
- Re‑using old primary cover gasket and derby cover o‑ring
- Over‑tightening primary cover screws and warping the cover
- Not cleaning old gasket material completely from the case and cover
- Forgetting to replace primary fluid after reinstall
- Pinching or misaligning the gasket around the starter and clutch areas
Comparison vs Stock/OEM
Compared to stock Harley paper primary gaskets, Cometic’s C9150 uses a high‑quality AFM/fiber composite that offers better sealing on slightly imperfect surfaces and is more resistant to tearing during installation or removal.
Improvements
- More durable than standard paper OEM gasket
- Better conformability to minor surface irregularities
- Less likely to stick and shred on disassembly
- Good long‑term oil resistance
Considerations
- Must be installed on properly cleaned and flat surfaces for best performance
- Though more reusable than paper, it is still best practice to replace when opened
Durability & Warranty
Expected Lifespan
Typically lasts until next primary teardown or clutch/compensator service; many riders run the same gasket for several years with no leaks when installed correctly.
Warranty
Standard Cometic limited manufacturer warranty against defects in materials and workmanship (length and terms vary by seller).
Maintenance
No direct maintenance; periodically inspect the primary for leaks at the gasket seam and replace if oil seepage is noted.
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