COMETIC - C9987 - Cylinder Base Gasket - 3.500" - Shovelhead
The COMETIC C9987 is a pair of cylinder base gaskets with a 3.500" bore designed for 1966-1984 Harley-Davidson street bikes, constructed with a Viton rubber coating bonded to a stainless steel core with a .001" thickness on both sides to resist fuel, prevent creeping and cracking, and provide long-term reliability — made in the USA.
Features
- High-quality products for long-term reliability
- Manufactured from premium fuel-resistant materials that will not creep, crack or become brittle
- Viton® gasket features a stainless steel core with a .001" thick coating of Viton rubber on both sides
- Made in the USA
Specs
- Material: Viton Coated Steel
- Thickness: 0.020"
- Type: Cylinder Base
- Units: Pair
- Thickness: 0.51 mm
- Product Name: Gasket
- Style: Standard
- Bore Size: 3.500"
- Riding Style: Street
Frequently Asked Questions - COMETIC - C9987 - Cylinder Base Gasket - 3.500" - Shovelhead - '66-'84 Harley-Davidson
How do I know if this part fits my vehicle?
Check the fitment information listed on this page against your exact year, make, model, and (where applicable) trim, engine size, or configuration. If your exact vehicle isn't listed, or you're not sure, use the product chat on this page or contact our support team before ordering - we're glad to help confirm fitment.
What does it mean if a product is listed as universal fit?
Universal fit means the product is designed to work across a range of vehicles, not that it's guaranteed to fit every one. Compare the listed measurements, mounting requirements, and connector or hardware specs against your specific vehicle before ordering, since some installations may need additional hardware or minor fabrication.
Where can I find installation instructions for this product?
General installation notes are provided above where available. For detailed step-by-step instructions, refer to the manufacturer's documentation included with the product, or use the product chat on this page for questions about difficulty, required tools, or whether professional installation is recommended.
What if I have more questions about this product?
Use the product chat on this page for fitment, specs, installation, and compatibility questions, or contact our support team directly for help before you order.
