Honda 90 Series Motorcycle Shop Manual (S90, CL90, CD90, C90, CT90)
S90 service documentation with engine, transmission, frame, electrical systems, troubleshooting guide, specifications and maintenance procedures for all models.
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Sample pages from the Honda 90 Series Motorcycle Shop Manual (S90, CL90, CD90, C90, CT90) manual
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Honda Models Covered & Key Technical Specifications
Models: Honda S90, CL90, CL90L, CD90, C90, CT90
Sub-models / Variants: 4-speed manual clutch (S90, CL90, CL90L, CD90), 3-speed automatic clutch (C90), 4-speed automatic clutch with low-range Posi-Torque (CT90)
Build Years: 1977–Onwards
Serial Numbers: CT90 from F. No. 000001A, CT90 from F. No. 122551, S90 from F. No. 90-674103, CL90 from F. No. 120015, CD90 from F. No. 201-168041
Technical Data:
- Engine: Air-cooled 4-stroke cycle, single cylinder tilted forward 75°
- Displacement: 89.6 cc (5.47 cu. in.)
- Bore x Stroke: 50 x 45.6 mm (1.97 x 1.80 in.)
- Compression Ratio: 8.2:1
- Max Output: 8.0 PS at 9,500 rpm (S90/CL90)
- Lubrication System: Trochoid pump, pressure feed
- Ignition Method: Battery ignition, 6V electrical system
Honda Manual Features & Content Preview
Honda 90 Series Motorcycle Shop Manual
- Covers the 1977–onwards Honda 90 series motorcycles including S90, CL90, CL90L, CD90, C90, and CT90 variants
- Official Honda Motor Co. publication 6220003, printed in Japan 1977
- Documents technical specifications, engine assembly diagrams, gear shift mechanism details, and carburetor tuning data across 186 pages
- File delivered as a direct download the moment payment clears
- Indexed PDF search covers every chapter and appendix
- Detailed cross-reference charts provided for carburetor setting and ignition timing parameters
- This 1977 shop manual remains the official reference for the Honda 90 series mechanical architecture and service maintenance procedures
Documentation Walkthrough
The 1977 Honda 90 series shop manual provides extensive mechanical documentation for the S90, CL90, CL90L, CD90, C90, and CT90 motorcycle line. The text is divided into foundational sections covering engine features, transmission systems, and frame geometry, followed by specialized chapters for the cylinder head, crankshaft, and transmission gear assemblies. Each section integrates detailed component analysis with construction diagrams, disassembly guides, and inspection criteria for wear limits. The manual also includes specific supplements for the CT90K2 through K8 and S90ZK1 variants, ensuring accurate coverage of the Positorque transmission mechanism and various carburetion configurations found throughout the production run.
Technical Depth and Data Highlights
Engine specifications are documented with precise tolerances for all models, such as standard valve clearance set at 0.05 mm and combustion chamber head volume between 18–18.4 cc. Transmission data is segmented by model, specifying primary reduction ratios of 3.72 for most units. The electrical system section provides headlight, taillight, and turn signal ratings for 6V configurations, supported by detailed wiring schematics. Cylinder head inspection data includes standard wear limits for valve stems and springs, ensuring engine performance remains within factory tolerances. For those seeking additional background, how factory workshop documentation is structured provides further insight into the depth of these technical assets. This 186-page official Honda Motor Co. publication is an indispensable reference for the 1977–onwards Honda 90 series, covering engine, chassis, fuel, and transmission specifications for the complete model range.
Document Reference: 6220003, SM B 7007910, Printed in Japan 1977
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