The Accossato 19x20 radial clutch master cylinder uses the largest piston in the clutch range, 19 mm, together with a 20 mm pivot distance, the shortest-stroke, firmest-pull setting Accossato builds for the clutch side. Accossato positions this combination for track and competition use rather than everyday road riding, since the longer pivot distance that produces a shorter lever stroke also demands more hand force. Supplied with a folding lever, long version, with relieving eyelet, it suits riders chasing the fastest possible clutch engagement on a superbike or naked flagship used mainly on circuit.

Key Features

• 19 mm piston diameter, the largest in Accossato's clutch range
• 20 mm pivot distance, the fastest and firmest clutch setting offered
• Folding lever, long version, fitted with a relieving eyelet (RST)
• CNC-machined aluminium body with a natural anodised finish
• Offset riser that reduces master cylinder deflection during gear changes
• Passive lever stroke cut by more than 50 percent versus a standard radial unit
• Stainless steel mounting screws and a galvanised steel bleed valve
• Seals manufactured from Formula 1 compound material

Construction and Material Quality

Accossato machines this master cylinder from aluminium billet on CNC equipment at its Italian facility, finishing the body in a natural anodised state. The hardware includes stainless steel screws and a galvanised steel bleed valve, while the internal seals are produced from Formula 1 compound to withstand sustained heat and contact with clutch fluid. A built-in offset riser resists flex of the unit as the lever is worked hard on downshifts, and the passive stroke before the clutch actually disengages is cut by more than half compared with a standard radial clutch master cylinder.

19 mm Piston and 20 mm Pivot for Fast Clutch Engagement

A 19 mm piston shifts more fluid per stroke than the 14 to 16 mm pistons used elsewhere in Accossato's clutch range, and here it is matched to a 20 mm pivot distance, which Accossato calls its fastest setting because the lever stroke needed to fully disengage the clutch is the shortest on offer. The compromise is hand effort: for the same clutch spring load, a longer pivot distance means more force is needed at the lever, which is why Accossato does not recommend this particular setting for road use and reserves it instead for track sessions and competition, where rapid, repeatable gear changes matter more than a light touch.

Fitment and Compatibility

This clutch master cylinder fits 60 motorcycles, almost entirely sports and naked flagships, including the Ducati Panigale V4, BMW S1000RR, Kawasaki ZX-10RR, Suzuki GSX-R1000, Aprilia RSV4 Factory and Honda CBR1000RR. Because several models are listed only for earlier production years than their later brake-side equivalents, the exact year range for each motorcycle is given in the Fitment tab. Confirm handlebar clamp diameter and clutch hydraulics on any bike not shown.

Road Approval

This master cylinder has no ABE documented; it is intended for track and competition use.

Scope of Delivery

Supplied in the box is the Accossato radial clutch master cylinder itself, assembled and ready to fit, together with its mounting hardware. The brake light switch sometimes fitted to the clutch side is not included and can be ordered separately under part number ID001 or ID002. The fluid reservoir is not included and is available separately in several styles.

Specifications

• Part number: CY038
• Type: Radial clutch master cylinder
• Piston diameter: 19 mm
• Pivot distance: 20 mm
• Lever: Folding, long, with relieving eyelet (RST)
• Body: CNC-machined aluminium, natural anodised
• Hose thread: M10x1
• Brake light switch: Not included (ID001 or ID002 separately)
• Reservoir: Not included
• Road approval: No ABE documented

• Aprilia DORSODURO 900 (2017–2019)
• Aprilia RS 660 (2021–2021)
• Aprilia RSV4 (2013–2015)
• Aprilia RSV4 1100 (2019–2021)
• Aprilia RSV4 R (2009–2019)
• Aprilia RSV4 RF (2015–2019)
• Aprilia RSV4 RR (2015–2019)
• Aprilia SHIVER 900 (2017–2019)
• Aprilia TUONO 660 (2021–2021)
• Aprilia TUONO V4 1100 (2015–2021)
• Aprilia TUONO V4 1100 FACTORY (2015–2020)
• Aprilia TUONO V4 1100 RR (2015–2018)
• BMW K 1300 R (2009–2016)
• BMW K 1300 S (2009–2015)
• BMW K1600 GT (2011–2017)
• BMW K1600 GTL (2011–2017)
• BMW M1000RR (2021–2021)
• BMW R NINET (2014–2016)
• BMW R1200R (2006–2015)
• BMW R18 (2020–2020)
• BMW S1000R (2014–2020)
• BMW S1000RR (2009–2018)
• Ducati DIAVEL (2011–2018)
• Ducati DIAVEL 1260 (2019–2019)
• Ducati HYPERMOTARD 821 (2013–2016)
• Ducati Hyperstrada 821 (2013–2016)
• Ducati MONSTER 1200 (2014–2017)
• Ducati MONSTER 796 (2011–2016)
• Ducati MONSTER 797 (2017–2017)
• Ducati MULTISTRADA 1200 (2015–2020)
• Ducati MULTISTRADA 1260 (2018–2020)
• Ducati MULTISTRADA 950 (2017–2017)
• Ducati Panigale 1199 (2012–2015)
• Ducati Panigale 1299 (2015–2018)
• Ducati Panigale 899 (2014–2015)
• Ducati Panigale V4 (2018–2021)
• Ducati SCRAMBLER 1100 (2018–2020)
• Ducati STREETFIGHTER V4 (2020–2021)
• Ducati X DIAVEL (2016–2021)
• Honda CB1000R (2018–2020)
• Honda CBR 1000 RR (2008–2019)
• Honda GL1800 GOLD WING (2018–2018)
• Honda VFR1200F (2010–2016)
• Honda VFR800X Crossrunner (2015–2015)
• Kawasaki GTR 1400 (2014–2017)
• Kawasaki NINJA H2 (2017–2019)
• Kawasaki NINJA H2 SX (2018–2021)
• Kawasaki NINJA H2R (2015–2015)
• Kawasaki Z1000 (2010–2016)
• Kawasaki Z1000SX (2011–2019)
• Kawasaki Z900RS (2018–2020)
• Kawasaki ZX-10 R (2006–2021)
• Kawasaki ZX-10 RR (2016–2021)
• Kawasaki ZX-6R (2003–2016)
• Kawasaki ZZR1400 (2006–2016)
• Suzuki GSX-R 1000 (2003–2017)
• Suzuki GSX-R1000R (2017–2017)
• Suzuki GSX-S1000 (2015–2021)
• Suzuki GSX-S1000F (2015–2017)
• Suzuki GSX-S1000GT (2022–2022)

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