Yoshimura Spark Arrester Kit SA-04-K | Yoshimura RS-4 Muffler 1.50-Inch | USFS Approved

The Yoshimura Spark Arrester Kit SA-04-K is a USFS-approved 1.50-inch spark arrester insert for Yoshimura RS-4 mufflers, supplied with the spark arrester insert, end-cap collar and set screw.

Nearly every public off-road riding area in the United States — national forests, BLM land and organized OHV parks — requires an approved spark arrester, and it is checked at staging areas. The RS-4 is one of Yoshimura's most widely fitted off-road canisters, and race-intent versions ship without an arrester, so this insert is what makes the bike legal for public land.

It drops into the muffler outlet and is retained by the supplied collar and set screw, so it comes out for closed-course days and goes back in for trail riding without pulling the muffler apart. It also serves as a replacement for an arrester that has clogged with carbon or been damaged.

• USFS approved spark arrester insert
• 1.50-inch size, for Yoshimura RS-4 mufflers
• Kit includes spark arrester insert, end-cap collar and set screw
• Adds spark arrester capability to RS-4 systems not originally equipped with one
• Removable and refittable without muffler disassembly
• Yoshimura part number 961-9027 (manufacturer part SA-04-K)

Required equipment for riding Yoshimura RS-4 equipped motocross, enduro and off-road machines in US Forest Service areas, BLM land and organized OHV parks. Confirm your muffler outlet is the 1.50-inch size before ordering — the 1.375-inch RS-4 uses kit SA-08-K instead.