Spark Exhaust dB Killer GP Style 32 mm 16° Open Universal G9922

The insert for Spark's GP Style case. Sixteen degrees of seat angle and a thirty-two millimetre bore, open rather than perforated.

Key Features

• dB killer for Spark GP Style silencers.
• Ø 47 mm outer, 32 mm internal bore.
• 16° seat angle.
• Open type — a plain restriction, no perforated wall.
• Stainless steel.
• Spark part number G9922, made in Mantova, Italy.

Sixteen Degrees

Spark's GP Style case is cut at a shallow slant, and the insert follows it. It is a different angle from every other Spark family — 18° on the old round cases, 34° on the newer round and Megaphone ones — and the angles are not close enough to force.

If the plug you have does not sit flush, you have the wrong article. That is the whole diagnosis.

Already Included, Usually

Spark ships the GP Style universal silencer with a removable db killer in the box. This article is the replacement: for the one that was lost during a rebuild, the one that stayed in a previous owner's toolbox, or the second one needed when a build runs two cases.

It is worth knowing before ordering. If your silencer is new and still boxed, the insert is already in there.

Open Rather Than Perforated

A straight-through restriction rather than a holed wall. The GP Style is a long, slim case with plenty of internal length to work with, so Spark took the simpler route: narrow the exit and let the case do the rest.

The result is less loss of flow than a perforated insert of the same bore, and a slightly smaller reduction in noise.

What It Does Not Change

The GP Style universal silencer has no homologation and cannot acquire one. The insert is a tool for getting through a circuit's noise check and for making a loud motorcycle liveable, not a route to a certificate.

Forty-Seven Millimetres of Body

The outer figure is what decides whether the insert seats at all. Forty-seven is the common size across Spark's round and GP Style cases, which is why the angle rather than the diameter is the thing that separates the articles in this part of the range.

One Per Case

Symmetrical, so there is no left or right. A build with two GP Style cases needs two of this article.