Target Audience:
Owners of 1977-1982 Honda CT90 and CT110 dual-sport motorcycles seeking to perform maintenance, repairs, or restoration.
Value Proposition:
Provides essential technical data and step-by-step procedures to keep these vintage Honda trail bikes running reliably, offering significant cost savings compared to professional shop labor.
Documentation Quality:
Features pictures, part diagrams, and detailed instructions, offering a visual and textual guide for repairs.
User Experience:
Enhanced by searchable text and clickable chapters for efficient information retrieval.
Customer Support:
Includes a free replacement guarantee for lost files.
Engine:
Complete overhaul and rebuild procedures, carburetor tuning (jetting, mixture screw adjustment), ignition system diagnostics (spark plug, coil, magneto), fuel system (tank, fuel line, fuel pump if applicable), lubrication system (oil change, viscosity recommendations, capacity)
Transmission:
Clutch system (operation, adjustment, replacement), transmission operation, gear shifting mechanisms, lubrication
Chassis And Suspension:
Front forks (oil change, seal replacement, adjustment), rear suspension (shocks/struts, swingarm lubrication and maintenance), wheel bearings, steering system, frame inspection and repair
Brakes:
Brake system maintenance (drum brakes typical for this era), adjustment, lining wear inspection, linkage maintenance
Electrical System:
Lighting system (headlight, taillight, indicators), charging system (rectifier, stator, battery charging issues), switches, wiring diagrams (implied by coverage of electrical system)
Bodywork And Fittings:
Body panels, fenders, seat, handlebars, fuel tank, exhaust system (muffler), plastics
Maintenance:
Scheduled maintenance, oil changes, filter replacements, chain adjustment, tire pressure, spark plug replacement, valve clearance checks and adjustments, battery maintenance
Troubleshooting:
Diagnostic procedures for common problems (e.g., no spark, starting issues, carburetor problems, electrical faults), error code identification (if applicable for the era, though less common than modern bikes), symptom-based troubleshooting guides
Repair And Rebuild:
Complete tear-down and reassembly instructions for major components, engine rebuilds, transmission repairs, suspension overhauls
Technical Specifications:
Torque specifications for critical fasteners, fluid capacities, recommended fluid types and viscosity, electrical specifications, engine dimensions (bore, stroke, compression ratio)
Depth:
Comprehensive (covers complete tear down and rebuild), suitable for DIY enthusiasts and professional mechanics
Engine Type Ct90:
Four-stroke, air-cooled, OHV, vertical single-cylinder
Engine Type Ct110:
Four-stroke, air-cooled, OHV, vertical single-cylinder
Displacement Ct90:
Approximately 89cc (actual displacement may vary slightly by specific sub-model within the CT90 range)
Displacement Ct110:
Approximately 105cc (actual displacement may vary slightly by specific sub-model within the CT110 range)
Horsepower Range:
Estimated 7-10 HP (exact figures vary by year and specific model variant, and are not always officially published for these utility bikes).
Torque Characteristics:
Designed for low-end torque for off-road capability.
Carburetor Type:
Typically a single downdraft carburetor (specific models like Keihin or Mikuni are often found).
Fuel Type:
Unleaded gasoline
Fuel Capacity:
Varies by model year and fuel tank size, typically around 1-2 gallons.
Ignition Type:
CDI (Capacitor Discharge Ignition) or Magneto ignition depending on the specific year and model.
Oil Type Recommendation:
Refer to manual for specific viscosity (e.g., SAE 10W-30 or 20W-40) and API classification.
Oil Capacity:
Typically around 0.8-1.0 liters (refer to manual for exact specification).
Dry Weight:
Typically in the range of 180-200 lbs (80-90 kg), varying by model year and specific features.
Gross Vehicle Weight Rating:
Not typically specified in detail for these vintage utility bikes, but designed for a single rider and light cargo.
Wheelbase:
Varies by model year, generally around 48-50 inches (122-127 cm).
Seat Height:
Designed to be relatively low for accessibility, typically around 30-31 inches (76-79 cm).
Safety Ratings:
No formal crash test ratings exist for this era of small-displacement dual-sport motorcycles. Safety relies on rider skill and proper maintenance.
Braking System:
Drum brakes front and rear.
Lighting:
Headlight, taillight, and potentially brake light and turn signals depending on regional specifications.
Frame Construction:
Robust steel frame designed for durability.
Oil Change Interval:
Typically every 1,000-2,000 miles or annually, but refer to the manual for specific recommendations based on usage.
Valve Clearance Check:
Recommended every 2,000-4,000 miles. Crucial for maintaining performance and engine health.
Spark Plug Replacement:
Intervals vary, but checking and cleaning is advised regularly. Replacement typically every 5,000-10,000 miles or as needed.
Chain Lubrication And Adjustment:
Regularly – every few hundred miles or after riding in wet/dirty conditions.
Engine Oil Viscosity:
Refer to manual for specific viscosity (e.g., SAE 10W-30, SAE 20W-40) and API service classification (e.g., SF or higher).
Brake Fluid:
Not applicable for drum brakes; maintenance involves lubrication and adjustment of cables/linkages.
Fork Oil Type:
Specific fork oil or ATF (Automatic Transmission Fluid) may be recommended; consult manual for viscosity and quantity.
Carburetor Fouling:
Common with older bikes due to fuel degradation; requires cleaning and proper jetting.
Electrical Component Failure:
Rectifier, stator, or CDI unit can fail over time, leading to charging issues or no spark.
Charging System Problems:
Often related to a failing rectifier or stator, resulting in a dead battery.
Worn Suspension Components:
Seals in forks can leak, and rear shocks can lose damping over time.
Cam Chain Tensioner Wear:
Can lead to rattling noises; requires adjustment or replacement.
Honda Motorcycle Division:
Honda has a long and storied history in motorcycle manufacturing, known for reliability, innovation, and accessible designs.
Ct Series Legacy:
The CT series, including the CT90 and CT110, are descendants of earlier Honda trail bikes, designed for utility, recreation, and off-road capability. They are iconic for their robust build and ease of use.
Ct90 Introduction:
The CT90 (Trail 90) was introduced in the mid-1960s and gained immense popularity as a versatile and durable off-road motorcycle.
Ct110 Introduction:
The CT110 (Trail 110) evolved from the CT90, offering a slightly larger engine displacement for increased power and performance, becoming a staple for recreational riders and postal services in some regions.
Production Period Covered:
1977-1982
Manufacturing Location:
Likely Japan, though some models may have had assembly in other regions.
