1990 Suzuki GS250FWS Service & Repair Manual (P/N 99500-32040-01E)

Suzuki's 1990 GS250FWS service manual, P/N 99500-32040-01E, covers the standard-specification liquid-cooled, four-cylinder DOHC model. The factory text notes that equipment may differ slightly by market.

Navigation and wiring detail: PDF text search and embedded bookmarks are not available. The main wiring diagram requires magnification, and some small wire-color codes remain difficult to distinguish.

• Engine repair: Engine removal, crankcase separation, cylinder-head service, piston and crankshaft inspection, valve timing, and cam chain tensioner installation.

• Clutch and transmission: Wet-clutch disassembly and inspection, gearbox reassembly, shift-fork checks, and gearshift mechanism servicing.

• Fuel and cooling systems: MIKUNI BSW24SS carburetor balancing, float-height checks, fuel-cock testing, water-pump installation, thermostat testing, and coolant bleeding.

• Electrical diagnosis: Transistorized ignition checks, generator and regulator/rectifier tests, starter-system inspection, cooling-fan tests, wiring diagrams, and switch-continuity charts.

• Chassis service: Anti-dive front-fork disassembly, steering-bearing replacement, full-floater suspension linkage inspection, front-brake bleeding, and rear drum-brake checks.

• Factory reference data: Periodic inspection and lubrication charts, tappet shim sizes, bearing-selection tables, torque specifications, fluid capacities, and wear limits.

Written primarily for experienced Suzuki mechanics, the manual also addresses apprentice and DIY mechanics; internal engine work calls for precision measuring equipment and the specified workshop tools.

Engine, Clutch and Transmission Repair

The five factory sections move from general information and component descriptions through inspection, disassembly, and service data. Identification, fluid recommendations, and break-in guidance precede the repair material.

Bearing selection: Crankshaft and connecting-rod inspections pair Plastigauge measurements with color-coded bearing-selection tables and a separate thrust-bearing chart. These references help match replacement bearings to the engine's identification codes and measured clearances before reassembly.

Tappet shim adjustment includes shim part numbers, while the timing illustrations show camshaft alignment and chain positioning. The crankcase assembly cautions explain how excess sealant can block oil passages and compromise bearing lubrication.

Clutch repair covers plate wear, driven-plate distortion, spring checks, and pushrod adjustment. The six-speed transmission drawings identify the countershaft, drive shaft, and shift-fork types, including the press-fitted second drive gear; a separate starter-clutch illustration identifies its rollers, springs, and push pieces.

BSW24SS Carburetors, Cooling and Lubrication

The carburetor material combines an exploded assembly view with diaphragm and needle-valve inspection, jet data, and synchronization using vacuum tester 09913-14420. Its cleaning cautions explain how needles or other probes can scratch passages and distort jet openings.

Cooling coverage follows the water pump and wax-pellet thermostat through component descriptions, installation illustrations, radiator-cap pressure checks, and coolant replacement with air bleeding.

Lubrication diagrams locate the oil pump, filter, jets, and oil pressure regulator. The blow-by gas recycling diagram shows the crankcase ventilation path through the cylinder-head cover and air cleaner.

Electrical Tests and Harness Routing

Electrical checks extend to the signal generator, ignitor, ignition coils, starter relay and motor, and fuel and temperature gauges. Ignition-system schematics and switch test charts support circuit diagnosis.

Regulator/rectifier resistance readings are specified for a Suzuki pocket tester, with a warning that other testers may give different results.

Separate GS250FW and GS250FWS wire-and-cable routing drawings distinguish harness placement. Additional views show carburetor air-vent hose routing and the rear spring-adjuster hose.

Fork, Suspension and Brake Coverage

Front-fork repair covers damper-rod removal, oil-seal installation, and separate left/right oil-fill data for the anti-dive assembly. Rear-suspension material details the swingarm, cushion rod, cushion lever, spherical ball, and assembly orientation.

Missing chassis pages: Printed pages 2-22, 3-13, and 4-56 are absent. These gaps affect the rear-brake/rear-wheel description, rear-shock inspection and adjustment, and the brake-service sequence. Available brake material includes disc inspection, a caliper section view, front-system bleeding, and rear drum/shoe checks.

Apply the factory specifications with proper mechanical training, and consult a qualified technician before undertaking brake or suspension repair beyond your experience.

Printable PDF and Included Pages

One printable PDF in English contains 122 pages total: 113 numbered technical pages plus 9 original cover, introductory, contents, and publication pages, all included in that total. There are no added advertising pages or separate supplements.