Yoshimura Low-Volume Sound Insert | Yoshimura RS-9 Muffler 1.25-Inch | Reduces Exhaust Noise

The Yoshimura Low-Volume Sound Insert is a 1.25-inch quiet insert for Yoshimura RS-9 mufflers, reducing exhaust noise so the same system can be run at sound-restricted tracks and events.

This is a sound insert, not a spark arrester — the two are different parts doing different jobs, and a sound insert does not make a machine legal for US Forest Service land. What it does is drop the measured dB reading, which is what stands between a race bike and a failed sound test at a club event or a track with a noise limit.

It fits into the muffler outlet and comes out again in seconds, so the bike can run open on an unrestricted day and quiet where it matters. Many riders simply keep one in the toolbox for the tracks that require it.

• Low-volume sound insert for Yoshimura RS-9 mufflers
• 1.25-inch size
• Reduces measured exhaust sound level for restricted tracks and events
• Fits and removes in seconds without muffler disassembly
• Not a spark arrester — does not satisfy USFS or BLM requirements
• Yoshimura part number 961-9018

Standard kit for anyone racing or doing track days on a Yoshimura RS-9 equipped machine where sound testing is enforced. Confirm your muffler outlet is the 1.25-inch size before ordering — the 1.125-inch version is part number 961-9033. If you need US Forest Service compliance rather than noise reduction, you need the RS-9 spark arrester kit SA-14-K instead.