Spark Exhaust Sinfonia Slip-On Pair Black Series Euro 4 Triumph Street Twin 900 (2017-2018) GTR0403BOM

The straight-sided Sinfonia body, blacked. It is the most restrained combination Spark offers for this motorcycle: a shape that does not announce itself and a finish that does not either, on a bike that was designed the same way.

Key Features

• Pair of Sinfonia slip-on silencers for the Triumph Street Twin 900, 2017 to 2018.
• Euro 4 homologated.
• AISI 304 stainless with black ceramic treatment.
• 3.5 kg against 7.5 kg standard.
• Square outlet, parallel body.
• 1,012 euro.

The Quietest Pair in the Range

Visually, not acoustically. The Sinfonia runs close to parallel and finishes square rather than tapering or slash-cutting, so it reads as a well-made standard part. Add a matte black surface and most people will not register that the exhaust has been changed at all — until the engine starts.

For a rider who wants the sound and the weight without the bike looking modified, this is the pair.

What 156 Euro Buys

The gap to GTR0403IOM, and nothing else changes: same body, same weight, same mounting, same approval. It is the clearest-cut finish decision in the whole Street Twin range, because there is no other variable to weigh against it.

Worth knowing before you decide: black ceramic hides road grime better than brushed stainless in winter, and shows dust more in summer. Neither is a reason on its own.

Living With a Ceramic Finish

Warm water and mild soap. Degreasers and the aggressive chemistry in car-wash products will make a ceramic surface patchy over a few seasons, and there is no way back from patchy other than replacing the silencer.

Done properly the finish outlasts several sets of tyres and comes through winter salt better than bare stainless does.

Approved as Delivered

Euro 4 homologation from the Italian Ministry of Transport, with the standard catalytic converter left in place. The coating plays no part in how the silencer meets the limit, so the certificate covers this version exactly as it covers the brushed one.

Four Kilos, and Where They Were

7.5 kg standard against 3.5 fitted. The factory silencers are large steel cans carrying a lot of internal chambering, and all of that mass sits high and behind the rear axle — the least useful place on a motorcycle to carry weight.

On a Street Twin the difference shows up first when you push the bike around a garage, and second in how quickly it settles when you change direction.

Sold as a Pair

Both silencers and the mounting hardware in one article. Spark does not split them, and on a symmetrical twin there would be no sense in it.

Installation

Slip-on level: the standard silencers come off and Spark's go on, header pipes untouched. The approval covers the exhaust as delivered, so nothing about the fitting is a compromise on the paperwork.

Fitment & Compatibility

Triumph Street Twin 900, 2017 and 2018. Brushed stainless version: GTR0403IOM. The other black pairs: GTR0401BOM (60's) and GTR0402BOM (Trumpet).

Road Approval

Euro 4 homologated, original catalyst retained.

Specifications

• Part number: GTR0403BOM
• Type: Slip-on, pair
• Design: Sinfonia
• Material: AISI 304 stainless steel, black ceramic treatment
• Weight: 3.5 kg (standard 7.5 kg)
• Road approval: Euro 4 homologated
• Fitment: Triumph Street Twin 900 (2017-2018)
• Manufacturer: Spark Exhaust Technology, Mantova, Italy