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Start ShoppingCometic C9689 Sportster Head/Base Gasket - MLS Multi-Layer Steel Gasket for High-Performance Engines
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Description
Upgrade your Sportster's engine performance with Cometic's premium MLS head/base gasket. Designed for maximum sealing efficiency and long-term durability, this gasket ensures optimal compression and prevents costly leaks in high-performance applications.
Key Features
- Multi-Layer Steel (MLS) Construction: Resists warping and heat degradation for consistent sealing under extreme engine conditions.
- Precision Fit for Sportster Engines: Engineered to match exact bore sizes (3.875 in.) and thickness (0.040 in.) for perfect compatibility.
- Lightweight Design (0.2 lbs): Reduces engine component stress while maintaining structural integrity and sealing performance.
Why Choose This Product
Cometic's MLS gasket outperforms standard alternatives with its advanced material composition and precise engineering. The 1.02 mm thickness ensures even pressure distribution, while the 98.43 mm bore size compatibility guarantees a flawless fit for Sportster engines. Riders benefit from enhanced engine efficiency, reduced maintenance costs, and prolonged gasket lifespan in demanding riding conditions.
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Upgrade your Sportster's engine performance with Cometic's premium MLS head/base gasket. Designed for maximum sealing efficiency and long-term durability, this gasket ensures optimal compression and prevents costly leaks in high-performance applications.
Key Features
- Multi-Layer Steel (MLS) Construction: Resists warping and heat degradation for consistent sealing under extreme engine conditions.
- Precision Fit for Sportster Engines: Engineered to match exact bore sizes (3.875 in.) and thickness (0.040 in.) for perfect compatibility.
- Lightweight Design (0.2 lbs): Reduces engine component stress while maintaining structural integrity and sealing performance.
Why Choose This Product
Cometic's MLS gasket outperforms standard alternatives with its advanced material composition and precise engineering. The 1.02 mm thickness ensures even pressure distribution, while the 98.43 mm bore size compatibility guarantees a flawless fit for Sportster engines. Riders benefit from enhanced engine efficiency, reduced maintenance costs, and prolonged gasket lifespan in demanding riding conditions.
| SKU | GM948C4E5F |
|---|---|
| MPN | C9689 |
| UPC/GTIN | 191070017958 |
| Brand | Cometic |
| Category | Gaskets/Seals |
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Featured Review
| Make | Model | Years |
|---|---|---|
| Harley-Davidson | Sportster (XL883, XL1200) | 1989-2003 |
| Harley-Davidson | Sportster (XL883, XL1200) | 2004-2021 |
Frequently Asked Questions
Yes, C9689 fits 1989-2021 Sportster models with 3.875" bore including XL883.
0.040" thickness; stock varies but this is a common performance thickness for better sealing.
No, designed as direct replacement for stock bore. Check compression ratio if doing high-performance build.
C9689 is the standard 0.040" MLS; -040 denotes thickness explicitly.
Installation Guide
Difficulty
Medium
Est. Time
1 hr 0 min
Tools Required
- torque wrench
- socket set
- gasket scraper
- engine stand (recommended)
Pro Tips
- Clean head and base thoroughly with brake cleaner. Torque in crisscross pattern to spec (typically 15-20 ft-lbs). Use moly paste on bolts.
Common Mistakes to Avoid
- Not cleaning mating surfaces thoroughly
- Incorrect torque sequence
- Reusing old bolts
Comparison vs Stock/OEM
MLS construction vs. stock composite/paper gasket
Improvements
- Superior sealing under high pressure/heat
- Resists warping and blowouts
- Supports higher compression ratios
Considerations
- Slightly thicker may raise compression slightly; more expensive than OEM
Durability & Warranty
Expected Lifespan
Engine life (100,000+ miles with proper install)
Warranty
1 year manufacturer defect warranty
Maintenance
Inspect during top-end service; no routine maintenance needed
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