1977-1983 Suzuki GS400, GS450 Twins Service & Repair Manual (P/N ISBN 0-89287-237-3)
Suzuki Models Covered & Key Technical Specifications
Models: Suzuki GS400, Suzuki GS425, Suzuki GS450
Sub-models / Variants: GS400, GS425N, GS425EN, GS425LN, GS450E, GS450ST, GS450LT, GS450LZ, GS450TZ, GS450TXZ, GS450ED, GS450LD, GS450TXD
Model Years: 1977–1983
Technical Data:
- Engine type: Air-cooled, 2-cylinder, 4-cycle, dual overhead camshaft (DOHC)
- Fuel octane requirement: 90 octane or higher
- Ignition timing (GS400/GS425): 10° BTDC at 1,500 rpm; 40° BTDC at 3,600 rpm
- Valve clearance: 0.03–0.08 mm (0.0012–0.0031 in.)
- Spark plug type: NGK B8ES or ND W24ES
- Fork oil capacity (GS450LZ): 189 cc (6.4 U.S. oz.)
- Standard compression pressure: 130–184 psi (GS400/GS425); 130–170 psi (GS450)
- Front axle nut torque: 3.6–5.2 mkg (26–38 ft-lb.)
- Handlebar clamp bolt torque: 1.2–2.0 mkg (9–14 ft-lb.)
Suzuki Manual Features & Content Preview
- Covers 1977–1983 Suzuki GS400, GS425, and GS450 twin-cylinder motorcycles across all displacement configurations.
- Official Clymer publication, third edition dated May 1985, ISBN 0-89287-237-3.
- Features 111 captioned service diagrams, 8 technical specification tables, and detailed exploded-view assembly guides for engine and chassis components.
- Includes critical model-year updates for 1982–1983 architectures not found in earlier GS-series releases.
Content Breakdown and Organization
Whether you are tearing down a top end or diagnosing a stubborn charging issue, this reference provides the exact structural layouts you need. It breaks down the engine, fuel, electrical, and suspension systems using clear imagery and component identification charts. Before initiating any heavy teardowns or altering suspension settings, always verify that your workspace meets standard shop safety practices and that the motorcycle is properly secured. The chapters start with fundamental guidelines for shop organization and tool selection. From there, it dives straight into the deep mechanical work. You get comprehensive visual guides for cylinder heads, valve trains, and crankcase assemblies. The indexed layout allows you to quickly flip between standard periodic maintenance schedules and complex mechanical overhaul breakdowns.
Specification and Data Preview
Having the right numbers on hand prevents costly mistakes in the shop. This reference-grade volume delivers exact torque requirements, fluid capacities, and electrical ignition settings for the entire 1977–1983 model run. Cylinder head bolt torque is mapped precisely at 26–29 ft-lb. When checking the valvetrain, intake clearance is listed at 0.03–0.08 mm. If you are servicing the front end, the fork oil level for the GS450LZ is documented at 117 mm. You will also find extensive tables for tappet shim sizes and compression pressure limits, allowing for precision engine tuning across all twin-cylinder variants.
Customer Reviews
Read what our customers say about this Suzuki Bike manual and share your own experience.