{"product_id":"spark-exhaust-db-killer-classic-sinfonia-32mm","title":"Spark Exhaust dB Killer Classic and Sinfonia 32 mm Open Universal G9939","description":"\u003cp\u003eThe insert that turns Spark's two long vintage cases from open pipes into something a neighbour will tolerate. Forty-seven millimetres across the body, thirty-two through the middle, a hundred long.\u003c\/p\u003e\u003ch2\u003eKey Features\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003edB killer for Spark Classic and Sinfonia silencers.\u003c\/li\u003e\n\u003cli\u003eØ 47.3 mm outer, 32 mm internal bore, 100 mm long.\u003c\/li\u003e\n\u003cli\u003eOpen type — a straight-through restriction with no perforated section.\u003c\/li\u003e\n\u003cli\u003eRemovable with the silencer in place.\u003c\/li\u003e\n\u003cli\u003eStainless steel.\u003c\/li\u003e\n\u003cli\u003eDoes not change the approval status of any silencer.\u003c\/li\u003e\n\u003cli\u003eSpark part number G9939, made in Mantova, Italy.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eOpen, and What That Means\u003c\/h2\u003e\u003cp\u003eSpark builds db killers in two kinds. Perforated ones move the gas through a wall of small holes; open ones simply narrow the exit. This is the second sort: a tube inside a tube, no holes, thirty-two millimetres of bore where the silencer would otherwise give you the full outlet.\u003c\/p\u003e\u003cp\u003eAn open insert is the gentler of the two on back pressure and the less effective of the two on noise. For a long vintage case that already has volume on its side, that is usually the right balance.\u003c\/p\u003e\u003ch2\u003eTwo Silencers, One Insert\u003c\/h2\u003e\u003cp\u003eThe Classic and the Sinfonia share this part. They are different shapes — one has a rolled mouth, the other is a plain even cone — but the outlet section is common to both, which is why Spark lists one article number for the pair.\u003c\/p\u003e\u003cp\u003eIf you have one of each on a twin, you need two of these.\u003c\/p\u003e\u003ch2\u003eA Hundred Millimetres\u003c\/h2\u003e\u003cp\u003eLength matters as much as bore. A hundred millimetres of restriction gives the gas column something to work against over a distance rather than at a single point, which is quieter and less abrupt than a short plug of the same diameter.\u003c\/p\u003e\u003ch2\u003eWhat It Will Not Do\u003c\/h2\u003e\u003cp\u003eIt will not make an unapproved silencer legal. Spark's vintage universal cases carry no homologation and no insert changes that: approval describes a complete system on a named motorcycle, and a piece of tube fitted into an outlet is not part of any such description.\u003c\/p\u003e\u003cp\u003eWhat it does is change what a meter reads at a circuit gate. That is a real and useful thing and it is the whole reason the article exists.\u003c\/p\u003e\u003ch2\u003eFitting and Removing\u003c\/h2\u003e\u003cp\u003eHand tools, silencer in place. The insert is retained at the outlet and comes out without disturbing the mounting or the link pipe — which is what makes it practical to run quiet on the way to a circuit and open once you are there.\u003c\/p\u003e","brand":"Spark Exhaust","offers":[{"title":"Default Title","offer_id":53617777377546,"sku":"G9939","price":421.05,"currency_code":"SEK","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0949\/7831\/0410\/files\/629071f72fb38_f0b5cabe-91ad-4f58-aed0-aaef2b09545c.png?v=1788354025","url":"https:\/\/inter-pace.com\/en-se\/products\/spark-exhaust-db-killer-classic-sinfonia-32mm","provider":"Inter-Pace","version":"1.0","type":"link"}