1. Introduction
This manual provides essential information for the proper installation, operation, and maintenance of your Vance & Hines 16672 Twin Slash Round Slip-On Exhaust System. These 4-inch chrome slip-on mufflers are designed for Harley-Davidson Touring models from 2017 and 2018, including Streetglide, Roadglide, Ultra, and Road King. They feature a distinctive twin slash end treatment and an all-mechanical straight-through louvered baffle designed to enhance power and produce a characteristic exhaust note.
The Twin Slash Round Slip-Ons are sold as a pair and are manufactured in the USA. For optimal performance, especially on motorcycles with Electronic Fuel Injection (EFI), the use of a Vance & Hines Fuelpak or Fuelpak FP3 Fuel Management System is recommended.
Figure 1.1: Vance & Hines 16672 Twin Slash Round Slip-On Exhaust installed on a Harley-Davidson Touring motorcycle.
2. Important Safety Information
Before proceeding with installation or operation, please read and understand all safety warnings and instructions. Failure to do so may result in injury or damage to the product or motorcycle.
- Always wear appropriate personal protective equipment, including eye protection and gloves, during installation.
- Ensure the motorcycle is stable and securely supported before beginning any work.
- Allow the exhaust system to cool completely before handling to prevent burns.
- Legal Disclaimer: Please check your respective state and local regulations to confirm noise and emission compliance before installing and operating this product. Due to state regulations, this item cannot be shipped to California addresses.
- Keep all packaging materials away from children.
3. Setup & Installation
This section outlines the general steps for installing your new Vance & Hines slip-on exhaust system. While installation is generally straightforward, professional installation is recommended if you are not familiar with motorcycle exhaust systems.
3.1. Tools Required
- 15mm deep socket
- 13mm deep socket
- Long ratchet handle
- Torque wrench (recommended for proper fastener tightening)
- Clean cloth
3.2. Installation Steps
- Ensure the motorcycle's exhaust system is cool to the touch.
- Locate and loosen the clamps securing the stock mufflers to the header pipes.
- Remove any mounting bolts or hardware holding the stock mufflers in place.
- Carefully slide the stock mufflers off the header pipes. The right-side muffler may require slightly more effort to remove.
- Inspect the header pipe ends for any debris or damage. Clean if necessary.
- Slide the new Vance & Hines Twin Slash Round Slip-Ons onto the header pipes. Ensure they are fully seated.
- Align the mounting brackets of the new mufflers with the motorcycle's frame mounting points. Secure with the appropriate hardware, but do not fully tighten yet.
- Tighten the muffler clamps to secure the slip-ons to the header pipes.
- Once the clamps are tightened, fully tighten the mounting bolts to the motorcycle frame. Refer to your motorcycle's service manual for specific torque specifications.
- Before starting the motorcycle, thoroughly clean the chrome surfaces of the new mufflers with a clean, soft cloth to remove any fingerprints or oils. This prevents staining once the exhaust heats up.
Figure 3.1: Rear view of the installed exhaust system.
Figure 3.2: Detail of the Twin Slash end treatment.
4. Operating Instructions
After successful installation, your Vance & Hines Twin Slash Round Slip-On Exhaust System is ready for use. These mufflers are designed to provide a deeper, more throaty exhaust note compared to stock mufflers, without being excessively loud or obnoxious.
- Initial Start-up: Start the motorcycle and allow it to idle. Listen for any exhaust leaks and ensure all connections are secure.
- Break-in Period: The exhaust note may evolve over the first 500 miles of riding as the internal components settle and carbon deposits form. The sound typically becomes richer and deeper over time.
- Fuel Management: For motorcycles equipped with Electronic Fuel Injection (EFI), it is highly recommended to install a Vance & Hines Fuelpak or Fuelpak FP3 Fuel Management System. This will optimize fuel delivery for the new exhaust system, ensuring proper engine performance and preventing potential issues like lean running conditions.
Figure 4.1: Side view of the motorcycle with the exhaust system.
5. Maintenance
Proper maintenance will ensure the longevity and appearance of your Vance & Hines exhaust system.
- Cleaning: Regularly clean the chrome surfaces with a non-abrasive chrome cleaner and a soft cloth. Always clean the exhaust when it is cool. Avoid cleaning when the exhaust is hot, as this can cause staining.
- Inspection: Periodically check all mounting hardware and clamps for tightness. Vibrations from riding can cause fasteners to loosen over time.
- Heat Shields: The full-coverage heat shields are designed to prevent bluing. Ensure they are clean and free from debris.
- Optional Quiet Insert: If you have installed an optional quiet insert, ensure it is securely in place and free from damage.
Figure 5.1: Integrated appearance of the exhaust system.
6. Troubleshooting
This section addresses common issues you might encounter.
| Problem | Possible Cause | Solution |
|---|---|---|
| Exhaust Leak / Hissing Sound | Loose clamps or improper seating of mufflers. | Check and tighten all muffler clamps and mounting bolts. Ensure mufflers are fully seated on header pipes. |
| Excessive Bluing/Discoloration | Improper cleaning, engine running too lean, or excessive heat. | Ensure exhaust is cleaned when cool. Consider installing a Fuelpak or Fuelpak FP3 to correct fuel mixture. Consult a professional mechanic if bluing persists. |
| Unusual Vibrations | Loose mounting hardware or improper alignment. | Verify all mounting bolts and clamps are securely tightened. Check for proper alignment of the mufflers. |
7. Product Specifications
| Feature | Detail |
|---|---|
| Model Number | 16672 |
| Brand | Vance & Hines |
| Compatibility | Harley-Davidson Touring Models (2017-2018), including Streetglide, Roadglide, Ultra, Road King, Freewheeler, and Tri Glide Models. |
| Muffler Diameter | 4 inches |
| Finish | Chrome, Painted Exterior |
| End Treatment | Twin Slash |
| Baffle Type | All-mechanical straight-through louvered baffle |
| Item Weight | Approximately 23.8 pounds |
| Product Dimensions (L x W x H) | 38 x 14 x 8 inches |
| UPC | 691852868070 |
| Manufacturer Part Number | 16672 |
| Country of Manufacture | USA |
7.1. What's in the Box
- Vance & Hines 16672 Twin Slash Round Slip-On Exhaust (Pair)
- Installation Hardware (if applicable, typically included with slip-ons)
- Instruction Sheet (refer to this manual for detailed guidance)
8. Warranty Information
Specific warranty details for the Vance & Hines 16672 Twin Slash Round Slip-On Exhaust are not provided in this document. For comprehensive warranty information, please refer to the official Vance & Hines website or contact their customer service directly. Keep your proof of purchase for any warranty claims.
9. Customer Support
If you require further assistance with installation, operation, or troubleshooting, please contact Vance & Hines customer support. Contact information can typically be found on the official Vance & Hines website or within the product packaging.
Note: Always refer to the latest official documentation from Vance & Hines for the most accurate and up-to-date information regarding your product.
