{"product_id":"yoshimura-sound-insert-kit-rs-12-muffler-1-500-ins-39-k","title":"Yoshimura SOUND INSERT KIT RS-12 Muffler, 1.500\" (INS-39-K)","description":"\u003cdiv class=\"trd trd--yoshimura\"\u003e\n\u003csection class=\"trd-hero\"\u003e\u003cp class=\"trd-eyebrow\"\u003eYoshimura · RS-12\u003c\/p\u003e\n\u003ch2 class=\"trd-headline\"\u003eLow-Volume Insert Kit for RS-12 Mufflers\u003c\/h2\u003e\n\u003cp class=\"trd-lead\"\u003eThe Yoshimura Sound Insert Kit RS-12 Muffler, 1.500\" is a replacement low-volume insert kit designed for Yoshimura RS-12 mufflers. This kit is listed for Yamaha YZ450F 2026–2027 fitment (see the fitment table below) and is intended for riders who need a different sound restriction setup for their specific application.\u003c\/p\u003e\n\u003cp class=\"trd-lead\"\u003eOffered as an optional kit on applications requiring different sound restrictions, this insert can be used to tune the exhaust note to match the needs of the bike and riding environment. Decibel reduction depends on application, and fitment should be confirmed using the insert chart referenced on the page.\u003c\/p\u003e\n\u003cul class=\"trd-chips\"\u003e\n\u003cli class=\"trd-chip\"\u003e\n\u003cspan class=\"trd-chip-label\"\u003ePart Number\u003c\/span\u003e\u003cspan class=\"trd-chip-value\"\u003eINS-39-K\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli class=\"trd-chip\"\u003e\n\u003cspan class=\"trd-chip-label\"\u003eSeries\u003c\/span\u003e\u003cspan class=\"trd-chip-value\"\u003eRS-12\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli class=\"trd-chip\"\u003e\n\u003cspan class=\"trd-chip-label\"\u003eFits\u003c\/span\u003e\u003cspan class=\"trd-chip-value\"\u003eYamaha YZ450F\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\u003c\/section\u003e\u003cdiv class=\"trd-cards trd-cards--3\"\u003e\n\u003carticle class=\"trd-card\"\u003e\u003cdiv class=\"trd-card-body\"\u003e\n\u003cp class=\"trd-label\"\u003eSound\u003c\/p\u003e\n\u003ch3 class=\"trd-card-title\"\u003eRS-12 Specific Design\u003c\/h3\u003e\n\u003cp class=\"trd-card-text\"\u003eBuilt specifically as a replacement service part for Yoshimura RS-12 mufflers, this sound insert kit is intended to restore or adjust an RS-12 setup without changing the muffler itself. It is also offered as an optional kit where different sound restrictions may be required.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/article\u003e\u003carticle class=\"trd-card\"\u003e\u003cdiv class=\"trd-card-body\"\u003e\n\u003cp class=\"trd-label\"\u003eInstallation\u003c\/p\u003e\n\u003ch3 class=\"trd-card-title\"\u003eNon-Spark Arrested\u003c\/h3\u003e\n\u003cp class=\"trd-card-text\"\u003eThis kit is identified as non-spark arrested. For riders selecting an insert based on event requirements or riding location rules, it is important to confirm the correct insert option for the intended application before installation.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/article\u003e\u003carticle class=\"trd-card\"\u003e\u003cdiv class=\"trd-card-body\"\u003e\n\u003cp class=\"trd-label\"\u003eIncluded\u003c\/p\u003e\n\u003ch3 class=\"trd-card-title\"\u003eComplete Insert Hardware\u003c\/h3\u003e\n\u003cp class=\"trd-card-text\"\u003eThe kit includes the key components needed for installation: a low-volume insert tube, an end-cap collar, and a set screw. With the correct parts included, it supports straightforward replacement of the insert components on compatible RS-12 muffler applications.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/article\u003e\n\u003c\/div\u003e\n\u003csection class=\"trd-story\"\u003e\u003cfigure class=\"trd-story-media\"\u003e\u003cimg class=\"trd-story-img\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0585\/4884\/6743\/files\/yoshimura-ins-39-k-rs12-main.jpg?v=1792280199\u0026amp;width=1400\" alt='Yoshimura SOUND INSERT KIT RS-12 Muffler, 1.500\" (INS-39-K) – Purpose-Built Replacement Kit' width=\"1400\" height=\"933\" loading=\"lazy\"\u003e\u003c\/figure\u003e\u003cdiv class=\"trd-story-copy\"\u003e\n\u003cp class=\"trd-label\"\u003eSound\u003c\/p\u003e\n\u003ch3 class=\"trd-story-title\"\u003ePurpose-Built Replacement Kit\u003c\/h3\u003e\n\u003cp class=\"trd-story-text\"\u003eAs part of Yoshimura’s Replacement Service Parts product line, the INS-39-K kit is designed to serve as a direct low-volume insert solution for RS-12 mufflers. It can be used as a replacement insert kit or as an optional choice on applications where different sound restrictions are required, helping tailor the exhaust setup without replacing the full muffler.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e\u003csection class=\"trd-story trd-story--text\"\u003e\u003cdiv class=\"trd-story-copy\"\u003e\n\u003cp class=\"trd-label\"\u003eFitment\u003c\/p\u003e\n\u003ch3 class=\"trd-story-title\"\u003eFitment and Verification\u003c\/h3\u003e\n\u003cp class=\"trd-story-text\"\u003eThis sound insert kit is listed for Yamaha YZ450F 2026–2027. Because insert compatibility can vary by application, fitment should be verified before purchase and installation. Reference the insert chart on the page and the fitment table below to confirm the correct match for the intended bike and RS-12 muffler configuration.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e\u003csection class=\"trd-story trd-story--text\"\u003e\u003cdiv class=\"trd-story-copy\"\u003e\n\u003cp class=\"trd-label\"\u003eInstallation\u003c\/p\u003e\n\u003ch3 class=\"trd-story-title\"\u003eInstallation Notes and Results\u003c\/h3\u003e\n\u003cp class=\"trd-story-text\"\u003eYoshimura notes that decibel reduction depends on application, so sound output changes will vary by how the muffler is configured and used. An installation PDF is provided on the page to support proper assembly and fit, using the included low-volume insert tube, end-cap collar, and set screw.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e\u003csection class=\"trd-section trd-section--specs\"\u003e\u003ch2 class=\"trd-section-title\"\u003eSpecifications\u003c\/h2\u003e\n\u003cdiv class=\"trd-table-wrap\"\u003e\u003ctable class=\"trd-table trd-table--specs\"\u003e\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\"\u003ePart Number\u003c\/th\u003e\n\u003ctd\u003eINS-39-K\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\"\u003eBrand\u003c\/th\u003e\n\u003ctd\u003eYoshimura\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\"\u003eProduct Line\u003c\/th\u003e\n\u003ctd\u003eReplacement Service Parts\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\"\u003eSeries\u003c\/th\u003e\n\u003ctd\u003eRS-12\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\"\u003eShipping Weight\u003c\/th\u003e\n\u003ctd\u003e0.25 lb\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth scope=\"row\"\u003eBarcode\u003c\/th\u003e\n\u003ctd\u003e00840025917903\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\u003c\/div\u003e\u003c\/section\u003e\u003csection class=\"trd-section trd-section--fitment\"\u003e\u003ch2 class=\"trd-section-title\"\u003eFitment\u003c\/h2\u003e\n\u003cdiv class=\"trd-table-wrap\"\u003e\u003ctable class=\"trd-table\"\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth scope=\"col\"\u003eMake\u003c\/th\u003e\n\u003cth scope=\"col\"\u003eModel\u003c\/th\u003e\n\u003cth scope=\"col\"\u003eModel Years\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\u003ctr\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003ctd\u003eYZ450F\u003c\/td\u003e\n\u003ctd\u003e2026–2027\u003c\/td\u003e\n\u003c\/tr\u003e\u003c\/tbody\u003e\n\u003c\/table\u003e\u003c\/div\u003e\n\u003cp class=\"trd-caption\"\u003eFitment as listed by Yoshimura for part number INS-39-K.\u003c\/p\u003e\u003c\/section\u003e\u003csection class=\"trd-section trd-section--docs\"\u003e\u003ch2 class=\"trd-section-title\"\u003eInstallation \u0026amp; Documents\u003c\/h2\u003e\n\u003cp class=\"trd-docs\"\u003e\u003ca class=\"trd-button\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0585\/4884\/6743\/files\/yoshimura-ins-39-k-installation-manual.pdf?v=1792280196\" target=\"_blank\" rel=\"noopener\"\u003eInstructions \/ What's Included (PDF)\u003c\/a\u003e\u003c\/p\u003e\n\u003cp class=\"trd-caption\"\u003eProvided by Yoshimura. Opens in a new tab.\u003c\/p\u003e\u003c\/section\u003e\n\u003c\/div\u003e","brand":"Yoshimura","offers":[{"title":"Default Title","offer_id":68080837361815,"sku":"INS-39-K","price":59.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0585\/4884\/6743\/files\/yoshimura-ins-39-k-rs12-main.jpg?v=1792280199","url":"https:\/\/allamericanktm.com\/products\/yoshimura-sound-insert-kit-rs-12-muffler-1-500-ins-39-k","provider":"All American KTM","version":"1.0","type":"link"}