Honda C50 / C50M / C50MK1 / S50 Service Manual • P/N SM 50/65
Honda Models Covered & Key Technical Specifications
Models: Honda C50, Honda C50M, Honda C50MK1, Honda S50
Sub-models / Variants: C50, C50M, C50MK1, C65, C65M, S50, S65
Model Years: Mid-1960s era Honda 50 and 65 series
Technical Data:
- Standard Tappet Clearance: 0.05 mm (0.002 in) for intake and exhaust
- Cylinder Compression: 12 kg/cm² (170 lb/in²)
- Engine Oil Capacity: 0.8 liters (1.7 U.S. pt)
- Spark Plug Gap: 0.6–0.7 mm (0.024–0.028 in)
- Fuel Tank Capacity: Approximately 4 liters
- Drive Chain: RK420-B high strength chain
- Transmission: 3-speed (C50/C65) or 4-speed (S50/S65)
Honda Manual Features & Content Preview
Honda C50, C50M, C50MK1, and S50 OEM Service Manual
- Covers 1960s-era Honda C50 and S50 series motorcycles, including the C50, C50M, C50MK1, C65, C65M, and S65 performance variants.
- Features 50+ detailed exploded-view technical illustrations and system diagrams to accurately map out every repair task.
- Instant digital download available immediately after your payment clears.
- Fully indexed PDF search functionality across every chapter, torque table, and appendix.
- Stored securely in your account for lifetime retrieval in case of a hard-drive failure.
Complete System Architecture
This 100-page factory document breaks down the internal systems of the original O.H.C. build. It provides exact factory specifications for the power transmission, specialized frame geometry, and core engine blocks. You get direct access to technical cross-sections of the trochoid oil pump, cylinder head design, and cam chain tensioner. The fuel delivery section specifically highlights needle clip positions and jet sizes for the PW16FA-series carburetors used across both the C50/C65 and S50/S65 lines.
Workshop Specifications and Diagnostics
Factory documentation assumes a baseline level of mechanical competence. Always verify that your tools and testing equipment are properly calibrated before servicing pressurized fuel lines or high-voltage ignition systems to prevent injury or component damage.
The manual lists standard clearances, pressure ratings, and electrical testing protocols directly from the Honda Motor Co., Ltd. Service Publications Office. Critical set-up numbers include a baseline engine compression pressure of 12 kg/cm² (170 lb/in²) and an ignition breaker point gap of 0.3–0.4 mm (0.012–0.016 in). Spark plug reach and heat ranges are also fully documented for quick referencing. Whether you are checking service tolerances against original charts or identifying component limits, this archive provides the raw technical data required for any vintage motorcycle repair.
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