Model Variants:
GS250, GS400, GS450, GSX250, GSX400, GSX450
Production Years Covered:
1979, 1980, 1981, 1982, 1983, 1984, 1985
Manual Product Code:
Likely a proprietary internal code for the seller, not a manufacturer's designation.
Segment:
Sportbike/Naked Bike segment, popular for their reliability and performance in the late 70s and early 80s.
Competitors:
Competed with models from Yamaha (XS series), Kawasaki (KZ series), and Honda (CB series) in similar engine displacements.
Features:
These motorcycles were known for their air-cooled, multi-cylinder engines, multi-stage gearboxes, and relatively accessible technology for their era. The GSX designation often indicated sportier styling and performance enhancements over the standard GS models.
Systems Covered:
Engine Mechanical, Engine Electrical, Fuel System, Ignition System, Lubrication System, Cooling System, Exhaust System, Transmission, Clutch, Chassis, Suspension (Front & Rear), Brakes (Front & Rear), Electrical System (Wiring Harness, Lighting, Ignition, Charging, Starting), Frame, Bodywork, Wheels & Tires, Controls, Specifications, Troubleshooting.
Estimated Page Count:
Estimates vary for such comprehensive manuals, typically ranging from 300 to 600 pages depending on the specific sub-models and detail level. Actual PDF page count will be confirmed by seller.
Type:
Workshop Repair and Service Manual
Engine Mechanical:
Detailed breakdown of engine components including cylinder head, valves, camshafts, pistons, connecting rods, crankshaft, timing system, and lubrication system with torque specifications and assembly procedures.
Fuel System:
Carburetor servicing and adjustment (e.g., Mikuni VM series often found on these models), fuel tank, fuel lines, and fuel pump operation.
Electrical System:
Comprehensive wiring diagrams, charging system (stator, regulator/rectifier), starting system (starter motor, solenoid), ignition system (CDI, ignition coils, spark plugs), lighting, and instrumentation.
Transmission Clutch:
Gearbox disassembly and assembly, clutch operation, friction plates, pressure plates, and transmission fluid specifications.
Suspension Brakes:
Front fork disassembly, seal replacement, rear shock absorber maintenance, brake caliper servicing, master cylinder overhaul, and bleeding procedures.
Routine Maintenance:
Oil changes, filter replacements, spark plug checks/replacement, air filter cleaning/replacement, chain adjustment, brake adjustments, and general lubrication.
Troubleshooting:
Systematic diagnostic procedures for common issues related to starting, engine performance, electrical failures, and braking problems.
Engine Rebuild:
Step-by-step instructions for engine disassembly, component inspection, measurement of wear limits, and reassembly of critical engine parts.
Electrical Diagnostics:
Guidance on using multimeters, checking continuity, voltage, and resistance to diagnose electrical faults using provided wiring diagrams.
Depth:
Comprehensive. Covers everything from basic preventative maintenance to in-depth engine and electrical system repairs, suitable for both amateur and professional mechanics.
Configuration:
Inline-twin, Inline-triple, or Inline-four cylinder configurations, air-cooled.
Displacement Range:
250cc, 400cc, 450cc (exact displacements vary by specific model within the GS/GSX series).
Bore Stroke:
Specifics vary by displacement, e.g., GS450 typically had a 62.4mm x 74.2mm bore x stroke.
Valve Train:
DOHC (Double Overhead Camshaft) or SOHC (Single Overhead Camshaft), depending on specific model. Typically 2 or 4 valves per cylinder.
Horsepower Range:
Approximately 20-45 HP, varying significantly by model and engine size.
Torque Range:
Approximately 20-35 Nm, varying by displacement and engine tune.
Carburetion:
Multiple carburetors (e.g., twin Mikuni VM series or similar), typically with choke operation. Specific jetting and adjustment data will be in the manual.
Fuel Type:
Unleaded gasoline, typically with an octane rating of 87 or higher.
Wheelbase:
Varies by model, typically around 1350-1450 mm.
Length:
Varies by model, generally between 2000-2200 mm.
Dry Weight:
Varies by model, typically in the range of 150-180 kg.
Fuel Tank Capacity:
Varies, commonly 13-16 liters.
Crash Test Data:
N/A (Motorcycles from this era were not subject to standardized crash testing in the same way as cars).
Braking System:
Front disc brake (single or dual depending on model) and rear drum brake. Some higher-spec models may have offered dual front discs.
Suspension:
Telescopic front forks, adjustable or non-adjustable rear shock absorbers (often twin shocks).
Lighting:
Headlight, taillight, brake light, turn signals.
Features:
Basic analog instrumentation including speedometer, tachometer, odometer, and warning lights. No advanced infotainment systems were present.
Features:
None. Driver assistance technologies were not a feature of motorcycles from this era.
Features:
No electronic connectivity features.
Oil Change:
Typically every 3,000-5,000 km or 6-12 months, whichever comes first. Manual will specify exact interval.
Spark Plug Check:
Every 5,000-10,000 km. Manual will list recommended spark plug types (e.g., NGK DPR8EA-9).
Valve Clearance Check:
Every 10,000-20,000 km. Manual will provide correct clearance specifications and adjustment procedures.
Engine Oil:
SAE 10W-40 or 20W-50 motorcycle-specific oil meeting API SE/SF or higher. Manual will specify exact viscosity and API rating. Capacity typically 2-3 liters.
Brake Fluid:
DOT 3 or DOT 4 brake fluid (check manual for specific recommendation).
Fork Oil:
Specific weight fork oil (e.g., 10W or 15W) and fill level. Manual will provide precise details.
Common Problems:
Carburetor synchronization issues, wear on cam chains, potential electrical component degradation (e.g., regulator/rectifier), clutch wear, fork seal leaks. The manual provides solutions.
Suzuki Legacy:
Suzuki has a long history of producing reliable and performance-oriented motorcycles, with a strong presence in racing and popular road bike segments.
Gs Series Era:
The GS series was Suzuki's flagship line of multi-cylinder motorcycles in the late 1970s and early 1980s, evolving from earlier twin-cylinder designs to more powerful four-cylinder variants and the technologically advanced GSX line.
Gsx Introduction:
The GSX designation introduced features like Anti-Dive front forks and improved engine tuning for enhanced sportbike performance. The 4-valve cylinder head technology also began to appear on some GSX models.
Manufacturing Origin:
Japan