Suzuki GSX-R600 Repair Manual (2004)

Suzuki introduced a substantially redesigned GSX-R600 for the 2004 model year. The K4 represented a major update to the middleweight GSX-R platform, with changes to the engine, frame, suspension, brakes, bodywork and electronics. Suzuki's 2004 annual report described the GSX-R600 and GSX-R750 as undergoing full model changes that year as part of an effort to strengthen the GSX-R range.

The 599 cc inline-four retained the 67.0 × 42.5 mm bore and stroke used by the preceding generation, but the engine received extensive internal changes. Titanium valves reduced valvetrain mass, while a 32-bit ECU controlled the electronic fuel-injection system. Suzuki's Dual Throttle Valve system used electronically controlled secondary throttle butterflies to improve response and fuel delivery across the rev range. Period reports quoted approximately 118 hp at 13,000 rpm.

Chassis development was equally significant. Suzuki narrowed and revised the twin-spar aluminum frame, adopted fully adjustable inverted front forks and fitted radial-mounted four-piston front brake calipers with a radial master cylinder. The revised geometry used a 23.15-degree rake and 93 mm trail, while the factory specifications listed a 1,400 mm wheelbase.

The redesigned GSX-R600 quickly established itself among the leading supersport motorcycles of the period. Cycle World selected the 2004 GSX-R600 as its Best Middleweight Streetbike, noting that the new model had also taken top honors in its 600 supersport comparison.

The K4 platform continued into 2005 as the K5, with comparatively minor changes rather than another complete redesign. Suzuki would replace it for 2006 with an all-new GSX-R600 featuring a more compact engine and chassis. Suzuki's own model archive describes the 2006 machine as a newly designed generation with a substantially smaller engine package and revised exhaust layout.