Spark Exhaust Force Evo 400 mm Silencer Group D.60 Titanium Kawasaki ZX-4RR (2023-2026) GKA8855ST

The long Force Evo case: 400 millimetres instead of 350, and the silencer Spark uses in the configuration it developed with Kawasaki Germany to stay within 98 decibels.

Key Features

• Force Evo silencer group for the Kawasaki ZX-4RR.
• Titanium case, 400 mm, carbon end cap.
• The case from Spark's 98 dB IDM system.
• 60 mm inlet.
• 761 euro, the dearest of the three silencer groups for this bike.
• Racing part, no homologation.

Fifty Millimetres of Quiet

Length is the cheapest way to take decibels out of an exhaust without strangling it. The extra fifty millimetres give the packing more volume and the gas a longer path through it, which is why the 400 mm case is the one in Spark's quietest ZX-4RR configuration and the 350 sits at 105 dB.

It is also why this group costs ninety-five euro more than the 350: there is simply more silencer.

The 98 dB System Uses Two Insert

Worth being precise about what belongs to what. Spark's complete 98 dB system, GKA8855T, is supplied with two dedicated dB killers. The article you are looking at here is the silencer group.

If the 98 dB figure is the reason you are ordering, tell us — we will confirm with Spark whether the inserts come with the group before anything ships, rather than let you assume it. Without them the case is a long Force Evo, not a 98 dB solution.

Room Behind the Shock

Four hundred millimetres has to go somewhere. On a standard ZX-4RR tail there is space, but a race seat unit, a tail tidy or an aftermarket hugger can turn the extra length into a clearance problem.

Measure before ordering rather than after. The 350 mm group GKA8852ST is the shorter alternative at the same interface.

Fitment & Compatibility

Kawasaki ZX-4RR of 2023 through 2026. This case belongs to the 98 dB system GKA8855T; ordered there, it arrives with the collector, the hangers and the two inserts. The shorter Force Evo is GKA8852ST at 666 euro, and the Konix Evo group is GKA8850ST.

Road Approval

None. Racing part. The 98 dB brief describes a paddock rule, not a road approval.

Specifications

• Part number: GKA8855ST
• Type: Silencer group
• Design: Force Evo
• Material: titanium, carbon end cap
• Length: 400 mm
• Inlet: 60 mm
• Belongs to: Spark's 98 dB configuration GKA8855T
• Road approval: none, track use
• Fitment: Kawasaki ZX-4RR (2023-2026)
• Manufacturer: Spark Exhaust Technology, Mantova, Italy