Target Audience:
Enthusiasts, DIY mechanics, and professional technicians working on vintage Honda ST50, CT70, and CT70H models.
Professional Level Documentation:
This manual is the same resource utilized by factory-trained technicians, ensuring accuracy and completeness.
Diy Empowerment:
Empowers owners to perform their own maintenance and repairs, saving money and enhancing vehicle longevity.
Step By Step Instructions:
Provides clear, sequential instructions for all repair and maintenance tasks.
Value Proposition:
Provides access to expert-level repair information, enabling owners to maintain and repair their classic Honda motorcycles effectively.
Manual Type:
Service and Repair Manual
Model Coverage:
Specifically covers Honda ST50, CT70, and CT70H models from 1969 to 1982.
Content Density:
High-density information packed into 131 pages, common for professional service manuals.
Compatibility:
Windows/Mac
Required Software:
Adobe PDF Reader
Engine:
Detailed coverage of engine disassembly, assembly, diagnosis, and repair.
Fuel And Lubrication:
Includes carburetor service, fuel tank, fuel lines, oil pump, and lubrication system.
Electrical System:
Covers ignition system, lighting, charging system, wiring diagrams, and component testing.
Chassis:
Includes frame, suspension (front and rear), steering, wheels, tires, and brakes.
Suspension:
Front telescopic forks and rear swingarm with dual shock absorbers, including adjustment and service.
Steering:
Handlebar, steering stem, bearings, and linkages.
General Information:
Provides an overview of the vehicle, safety precautions, and general maintenance principles.
Periodic Maintenance:
Detailed schedules and procedures for routine maintenance tasks.
Tune Up:
Step-by-step instructions for engine tune-up, including carburetor adjustment, ignition timing, and spark plug replacement.
Servicing Information:
Comprehensive repair and diagnostic procedures for all major vehicle systems.
Troubleshooting:
Detailed troubleshooting sections for common problems, guiding users through diagnostic steps.
Specifications Data:
Includes critical torque values, clearances, fluid capacities, and diagnostic specifications.
Diagnostic Capabilities:
Advanced troubleshooting guides and diagnostic procedures for identifying and resolving common and complex issues.
Repair Scope:
Covers everything from minor adjustments to complete engine rebuilds and major component overhauls.
Wiring Diagrams:
Includes comprehensive electrical wiring diagrams for accurate diagnosis and repair of the electrical system.
Engine Type:
Air-cooled, four-stroke, OHC single-cylinder (typical for these models).
Displacement St50:
49cc (common for ST50 variations)
Displacement Ct70:
72cc (common for CT70 variations)
Engine Cooling:
Forced air cooling.
Horsepower Range:
Typically in the 4-7 hp range, depending on specific model and tuning.
Torque Specs:
Refer to manual for specific torque values for engine components.
Carburetor Type:
Keihin carburetors (common models: PB16, PB18, etc., specific to engine size and year).
Fuel Type:
Unleaded gasoline.
Fuel Delivery:
Gravity feed from fuel tank to carburetor.
Oil Type:
Honda Motorcycle Oil (e.g., 10W-30, 10W-40, refer to manual for exact specification).
Oil Capacity:
Refer to manual for specific oil capacity (typically around 0.7-0.9 liters).
Transmission Type Ct70:
3-speed semi-automatic clutch (CT70).
Transmission Type Ct70H:
4-speed manual clutch (CT70H).
Transmission Type St50:
Often equipped with an automatic centrifugal clutch or a 3-speed semi-automatic transmission, depending on the specific ST50 variant.
Clutch Operation:
Automatic centrifugal for some ST50 models, manual operation for CT70H, and semi-automatic for CT70.
Gear Ratios:
Detailed gear ratios for all models and transmissions provided within the manual.
Final Drive:
Chain drive.
Transmission Fluid:
Motorcycle engine oil is typically used in the transmission/crankcase of these models. Refer to manual for specific type and viscosity.
Wheelbase:
Refer to manual for specific wheelbase dimensions for each model.
Tire Size Front:
Refer to manual for specific OE tire sizes (e.g., 2.50-10, 2.50-12, etc.).
Tire Size Rear:
Refer to manual for specific OE tire sizes (e.g., 2.50-10, 2.75-10, 3.00-10, etc.).
Wheel Bolt Pattern:
Not applicable; wheels are typically hub-mounted with brake drums.
Dry Weight:
Typically in the range of 70-80 kg, depending on model and equipment.
Oil Change Interval:
Typically every 1,000-2,000 km or 6-12 months, refer to manual for precise intervals.
Spark Plug Replacement:
Recommended at specified mileage intervals or as part of tune-up procedures.
Valve Clearance Adjustment:
Periodic adjustment is critical for engine performance and longevity; detailed procedures in the manual.
Brake Fluid:
Not applicable for drum brakes; refer to manual for any specific lubrication for brake components.
Fork Oil Type:
Refer to manual for recommended fork oil viscosity and type (e.g., SAE 10W).
Carburetor Clogging:
Common issue with older carbureted vehicles due to fuel varnish; manual provides cleaning and adjustment procedures.
Ignition System Wear:
Points, condenser, and coils can wear over time; manual details testing and replacement.
Tire Wear:
Regular inspection of tire condition and pressure is important.
Chain Tension:
Requires regular adjustment to prevent premature wear and ensure safe operation.
Honda Motorcycle Division:
Honda's reputation for reliable and innovative small-displacement motorcycles is well-established.
Ct70 Heritage:
The CT70 (and its siblings) was part of Honda's hugely successful 'mini-bike' revolution, offering accessible and fun off-road and street-legal riding.
St50 Role:
The ST50 served as a more accessible, often street-legal, counterpart to the off-road focused CT models.
Manufacturing Location:
Primarily manufactured in Japan.
