Honda ST50 / ST70 / CT70 Factory Shop Manual (OEM)
Honda Models Covered & Key Technical Specifications
Models: Honda ST50, ST70, CT70
Sub-models / Variants: U.K. Type, General Export Type, U.S.A. Type
Model Years: 1969–1976
Technical Data:
- Engine type: Air-cooled, 4-stroke O.H.C single-cylinder
- Displacement: 49 cc (ST50), 72 cc (ST70, CT70)
- Compression ratio: 8.8:1
- Transmission: 3-speed constant mesh
- Clutch: Wet, multi-plate, automatic centrifugal type
- Fuel capacity: 2.5 L (ST50/70), 5.5 L (CT70)
- Ignition: Flywheel magneto
- Battery: YUASA B60-6 6V 2AH
Honda Manual Features & Content Preview
- Covers 1969–1976 Honda ST50, ST70, and CT70 trail and road variants across domestic and export configurations
- Authentic OEM 1970 Honda Motor Co., Ltd. technical documentation
- Features 49 pages of unedited factory data detailing the 4-stroke O.H.C. single-cylinder engine platform
- Includes 47 technical diagrams, 4 detailed wiring schematics, and 2 extensive torque specification tables
Engine and Chassis Documentation
This workshop manual provides deep insight into the power unit and chassis of the classic Honda mini-bike lines. It documents the exact specifications for engine removal, installation, and complete lubrication system overhauls. Inside, you will find detailed breakdowns of the 3-speed constant mesh transmission internal components. Need to verify the kick starter mechanism construction? The reference highlights that, alongside critical piston, crankshaft, and cylinder head assembly data. It also details the precise operation of the cam chain tensioner.
Having exact factory documentation saves valuable hours on the bench when aligning frame components or tracing faults. Frame documentation covers the front and rear fork assemblies, internal expanding shoe brakes, and wheel hub construction. Naturally, when reviewing fuel systems and electrical schematics for a rebuild, always maintain a well-ventilated workspace and adhere to standard shop safety protocols. The text additionally outlines drive chain maintenance and air cleaner element service intervals.
Technical Data and Electrical Specifications
Precision is everything during a vintage restoration. This manual lists essential clearance values, torque limits, and performance metrics directly from Honda engineers. For instance, the cylinder head specification table sets the intake valve clearance at 0.11–0.20 mm. Engine data requires cylinder head bolt torque to be exactly 6.5–9 ft-lbs. Performance-wise, it documents the ST70 maximum horsepower at 5.6 hp at 8000 rpm.
Dealing with 6V electrical systems requires accurate schematics. The reference material includes wiring diagrams tailored for U.K., U.S.A., and other export models. These pages define vital parameters for the flywheel AC generator performance and battery charging rates, giving mechanics exactly what they need to diagnose charging issues effectively.
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