How to Replace the End Cap on a Yoshimura R-77 Muffler

By Yoshimura R&D of America, Inc. | Published: 2026-10-19

Category: How-to Guides

Step-by-step guide to swapping the slash-cut end cap on your Yoshimura R-77 muffler using the R-77 Replacement End Cap Kit. Includes tools, tips, and common mistakes.

Quick Answer

Replace the slash-cut end cap on your Yoshimura R-77 muffler using the R-77 Replacement End Cap Kit. The swap requires basic hand tools and about 20 minutes, but getting the rivet band alignment right is the most common mistake.

When to Replace the End Cap

End caps take the brunt of heat, road debris, and vibration. Over time the carbon fiber can show surface crazing, the rivet band can loosen, or you may simply want a fresh look. The R-77 Replacement End Cap Kit is designed for left-side R-77 mufflers with a round, slash-cut outlet. It includes everything you need for a complete swap without sourcing extra parts.

What the Kit Includes

The kit comes with a high-gloss carbon fiber end cap, rivets, a rivet band, and an insert hole grommet. All parts are made in Yoshimura's composites shop in Chino, California, using heat-resistant impregnated carbon fiber. The pre-installed rivet band saves a step, but you still need to secure it evenly during installation.

Step-by-Step End Cap Replacement

Remove the Old End Cap: Secure the muffler in a soft-jaw vise or on a clean workbench. Drill out the existing rivets using a 1/8-inch drill bit. Work slowly to avoid enlarging the holes in the muffler shell. Once all rivets are removed, pull the old end cap and rivet band free. Drill only deep enough to separate the rivet head; going too deep can damage the muffler body.
Clean the Muffler Mating Surface: Wipe the inside edge of the muffler outlet with a clean rag and rubbing alcohol. Remove any old adhesive or carbon residue. A clean surface ensures the new rivet band sits flat and the end cap seals evenly. Leftover debris can cause the new cap to sit crooked, leading to exhaust leaks or rattles.
Position the New Rivet Band and End Cap: Slide the new rivet band onto the muffler outlet, then press the carbon fiber end cap into place. Align the rivet holes in the band with the original holes in the muffler. Hold the cap firmly so it doesn't shift while you start the first rivet. If the rivet band rotates during installation, the holes will misalign and you may need to drill new ones.
Install the Rivets: Insert the supplied rivets through the rivet band and into the muffler holes. Use a hand riveter to pull each rivet, working in a star pattern (top, bottom, left, right) to distribute pressure evenly. Pull until the rivet stem snaps cleanly. Over-crimping or pulling at an angle can crack the carbon fiber or leave a loose rivet.
Insert the Grommet and Final Check: Press the insert hole grommet into the center hole of the end cap. Give the cap a gentle tug to confirm all rivets are seated. Start the bike and listen for any air leaks around the cap edge. A missing or loose grommet can cause a whistling sound at idle.

Product Details

R-77 REPLACEMENT END CAP KIT SLASH-CUT LEFT SIDE: Fits left-side R-77 mufflers with a round, slash-cut outlet. Made in Chino, California with heat resistant impregnated, high gloss lightweight carbon fiber. This kit is application-specific; it won't fit right-side mufflers or non-slash-cut outlets, so confirm your muffler orientation before ordering.
R-77 REPLACEMENT END CAP KIT SLASH-CUT LEFT SIDE