1978–1983 Suzuki GS850G Service Manual (P/N 99500-38002-03E)

• 660 PDF pages in two files: a 454-page June 1983 sixth-edition Suzuki service manual, Manual No. 99500-38002-03E, plus a 206-page February 1979 GS850GN factory manual scan.
• Model coverage: GS850GN and the GS850GT, GS850GLT, GS850GX/GLX, GS850GZ/GLZ, and GS850GD/GLD variants, covering the supplied 1979–1983 factory material.
• Engine repair depth: engine removal and installation, compression testing, cylinder-head and valve service, camshaft and cam-chain work, piston and cylinder inspection, crankshaft checks, lubrication-system service, clutch repair, and five-speed transmission work.
• Shaft-drive setup: secondary and final bevel-gear disassembly, bearing preload and shim selection, backlash measurement, tooth-contact inspection, final-drive reassembly, and propeller-shaft installation.
• Fuel and electrical changes: VM26SS and BS32SS carburetor service, fuel-level checks, four-carburetor synchronization, ignition and charging tests, starter and lighting diagnosis, emissions-system inspection, and model-specific wiring diagrams.
• Chassis and reference material: front-fork overhaul, wheel and steering service, master-cylinder and caliper repair, brake bleeding, cable and hose routing, special-tool listings, torque tables, wear limits, capacities, and electrical test data.

This factory-issued Suzuki manual set is built around the 843 cc air-cooled DOHC four-cylinder GS850G and its shaft-drive chassis. The June 1983 volume identifies itself as the sixth edition of a manual first issued in January 1979. Its depth and reliance on precision measurement, carburetor balancing equipment, and Suzuki service tools make it best suited to experienced mechanics and advanced DIY owners.

How the Coverage Is Organized

The later model sections are supplements, not stand-alone repair manuals. Each directs the technician back to the GS850GN base chapters, then documents the specifications, component changes, and repair procedures unique to that version. That structure matters when tracing a GT, GLT, GX/GLX, GZ/GLZ, or GD/GLD fault: the base procedure and the applicable model supplement must be used together.

The variant material follows real production changes. The GS850GN uses Mikuni VM26SS carburetors, breaker-point battery ignition, and combined electric/kick starting. The GS850GT section covers the switch to Mikuni BS32SS variable-venturi carburetors, transistorized ignition, electric-only starting, revised brakes, and related fuel-system and electrical repair procedures. GX/GLX coverage adds camshaft-sprocket fastener changes, driven-gear shift-fork and shift-spring revisions, universal-joint flange and propeller-shaft changes, and a separate GLX front-fork overhaul. GZ and GLD sections cover electronic timing advance and ignitor/signal-generator testing. For the GZ, the revised cylinder head, head cover, and cam-timing arrangement is identified as effective from engine No. GS850G-755015.

Repair and Diagnostic Detail

Engine chapters go well beyond routine service. They cover top-end removal and inspection, valve-guide replacement and reaming, cam timing, piston and ring checks, crankcase and crankshaft work, oil-pump inspection, clutch assembly, transmission shafts, shift components, and final operational adjustments. Separate troubleshooting tables address engine, chassis, and electrical faults.

The shaft-drive chapter is especially detailed, with a final gear case breather-circuit view, bearing and seal procedures, preload adjustment, shim tables, backlash measurement, tooth-contact pattern checks, and final assembly. The manual lists purpose-built tools such as the secondary-drive bevel-gear holder 09924-54511, backlash measuring tool 09924-34510, carburetor balancer 09913-13121, fuel-level gauge 09913-14511, and compression gauge 09915-64510.

Drawing coverage includes model-specific full wiring diagrams; wire, cable, and brake-hose routing views; the final gear case breather circuit; bevel-gear tooth-contact patterns; transistorized and electronic timing-advance diagrams; and GS850GLX front-fork assembly views. Engine and chassis torque tables are paired with general bolt-grade charts, service limits, clearance and wear data, fluid and lubrication specifications, and electrical test values.

The manual warns that final-drive shims must be retained and that drive and driven bevel gears are a matched pair; incorrect parts or shim placement can destroy the required preload and tooth contact. It also flags model-specific hazards such as a misrouted GT clutch cable being damaged by cylinder heat and non-specified or spilled brake fluid damaging brake-system components and finishes.

Brake, steering, wheel, and driveline repair can directly affect vehicle control. Follow the model-specific cautions, inspection limits, torque data, and final checks before returning the motorcycle to service.