🏷️ Basic Information

Make:

Honda

Model:

CT90 Trail 90

Vehicle Chassis Codes Ct110:

Refer to manual for specific chassis codes by year

Vehicle Chassis Codes Ct90:

Refer to manual for specific chassis codes by year

Ct110 Generation Info:

This manual covers the primary generation of the CT110 Postie Bike.

Ct90 Generation Info:

This manual covers various iterations of the CT90 Trail 90, which saw significant updates and variations over its production run.

👋 Introduction

Target Audience:

Owners, mechanics, and enthusiasts of Honda CT110 and CT90 Postie Bikes/Trail 90s who wish to perform their own maintenance and repairs.

Value Proposition:

Provides a cost-effective solution for maintaining and repairing these iconic motorcycles, empowering users with the knowledge typically reserved for professional workshops.

Ease Of Use:

Features easy-to-follow step-by-step instructions and illustrations to simplify complex repair tasks.

Accessibility:

Downloadable format compatible with PCs, Macs, tablets, and smartphones; printable for convenient workshop use.

Completeness:

Covers all service and repair procedures from A-Z for the specified models and years.

📋 Manual Details

Manual Coverage Years:

1978-2005 (for CT110, specific years may vary slightly for CT90 within this range where overlap occurs)

Engine Variants Covered:

All CT110 and CT90 engine variants, including potential minor updates over the years.

Trim Levels Covered:

All trim levels and configurations are covered as applicable to the CT110 and CT90 models.

Transmission Types Covered:

All transmission types, predominantly automatic centrifugal clutch with 4-speed gearbox.

Estimated Page Count:

Comprehensive, likely over 300-400 pages given the scope and detail for two models over many years.

Manual Type:

Complete Workshop Service Repair Manual

Language:

English

Format Type:

Digital Downloadable (PDF)

📖 Manual Coverage

Engine System Coverage:

Engine removal, disassembly, inspection, repair, and reassembly; cylinder head, piston, crankshaft, camshaft, valve train, lubrication system, cooling system (air-cooled).

Fuel System Coverage:

Carburetor identification, removal, cleaning, adjustment, and troubleshooting; fuel tank, fuel lines, fuel filter.

Transmission System Coverage:

Clutch operation, maintenance, and repair; gearbox internal inspection and service; final drive inspection and service.

Electrical System Coverage:

Ignition system (CDI, spark plug), lighting system (headlight, taillight, turn signals), charging system (alternator, battery), wiring diagrams, troubleshooting of electrical components.

Brake System Coverage:

Front and rear brake system maintenance, adjustment, and component replacement (drum brakes primarily).

Suspension System Coverage:

Front fork maintenance, seal replacement, fluid changes; rear shock absorber inspection and replacement.

Chassis Frame Coverage:

Frame inspection for damage, steering head bearing maintenance and adjustment.

Wheel Tire Coverage:

Wheel bearing inspection and service, tire pressure checks, tire replacement.

Bodywork Fairings Coverage:

Panel removal and installation, minor bodywork repair guidance.

Routine Maintenance Procedures:

Oil changes, filter replacements, air filter cleaning/replacement, spark plug checks/replacement, chain adjustment and lubrication, tire pressure checks, brake adjustments, general lubrication.

Troubleshooting Procedures:

Step-by-step diagnostic guides for common issues related to starting, engine performance, electrical faults, and braking.

Repair Procedures:

Detailed instructions for engine overhauls, transmission repairs, carburetor rebuilds, electrical system fixes, suspension component replacement, and brake system servicing.

Disassembly Reassembly Procedures:

Comprehensive guides for dismantling and reassembling major vehicle components with torque specifications and critical clearances.

Inspection And Adjustment Procedures:

Procedures for checking wear and tear on components, adjusting controls, and ensuring proper operation.

Depth Of Information:

Complete rebuild capability; covers everything from basic user maintenance to in-depth mechanical and electrical repairs, suitable for both novice DIYers and experienced mechanics.

📊 Manual Specifications

File Format:

PDF (Portable Document Format)

Print Quality:

High-resolution scans with clear text and legible images, designed for printing.

Binding Type:

Not applicable (Digital Download)

Paper Type:

Not applicable (Digital Download)

⚙️ Engine Specifications

Ct110 Engine Type:

4-stroke, OHC, air-cooled single-cylinder

Ct110 Engine Displacement:

Approximately 105cc

Ct90 Engine Type:

4-stroke, OHC, air-cooled single-cylinder

Ct90 Engine Displacement:

Approximately 89cc

Engine Bore X Stroke Ct110 Approx:

Refer to manual for exact specifications (typically around 50mm x 53mm)

Engine Bore X Stroke Ct90 Approx:

Refer to manual for exact specifications (typically around 47mm x 50.6mm)

Horsepower Output Ct110 Approx:

Refer to manual for specific model year output (typically 7-9 HP)

Horsepower Output Ct90 Approx:

Refer to manual for specific model year output (typically 6-8 HP)

Carburetor Type Ct110:

Keihin carburetor (specific model varies, e.g., PB16, PB18)

Carburetor Type Ct90:

Keihin carburetor (specific model varies, e.g., PB10, PB16)

Fuel Type Recommendation:

Unleaded gasoline (refer to manual for octane rating, typically 86 or higher)

Fuel Tank Capacity Ct110 Approx:

Refer to manual for specific year (typically around 4.0 - 5.0 Liters)

Fuel Tank Capacity Ct90 Approx:

Refer to manual for specific year (typically around 3.0 - 4.0 Liters)

🔧 Transmission

Transmission Type:

4-speed manual transmission with automatic centrifugal clutch

Transmission Variations:

Some CT90 models might have had slight variations in gear ratios or clutch engagement characteristics. CT110 is generally consistent.

Clutch Operation:

Automatic centrifugal clutch requires no manual clutch lever operation; engagement is automatic based on engine RPM.

Final Drive Type:

Chain drive

Gear Selection Method:

Foot shifter

📐 Dimensions

Overall Length Ct110 Approx:

Refer to manual for specific year (typically around 1.9 meters)

Seat Height Ct110 Approx:

Refer to manual for specific year (typically around 0.75 meters)

Curb Weight Ct110 Approx:

Refer to manual for specific year (typically around 95-105 kg)

Curb Weight Ct90 Approx:

Refer to manual for specific year (typically around 85-95 kg)

🛡️ Safety Features

Safety Rating Context:

As these are older, small displacement motorcycles, formal crash test ratings as seen on modern cars are not applicable. Safety focus is on proper maintenance and rider awareness.

Lighting System:

Headlight, taillight, brake light, and often turn signals (depending on market specification) for visibility and signaling.

Braking System:

Front and rear drum brakes, designed for adequate stopping power for the vehicle's capabilities.

Frame Construction:

Robust steel frame designed for durability and stability.

💡 Technology Features

Infotainment System:

None. These are utility motorcycles focused on mechanical function.

Driver Assistance Features:

None. Relies on rider skill and basic instrumentation.

Connectivity Features:

None.

🔧 Maintenance

Engine Oil Change Interval:

Refer to manual; typically every 1000-2000 km or annually, whichever comes first.

Air Filter Cleaning Interval:

Refer to manual; typically every 1000-2000 km, more frequently in dusty conditions.

Spark Plug Check Interval:

Refer to manual; typically every 3000-5000 km.

Valve Clearance Adjustment Interval:

Refer to manual; typically every 6000-10000 km or as needed.

Engine Oil Type Recommendation:

SAE 10W-30 or 10W-40 API SE, SF or SG classification motorcycle oil (refer to manual for exact specification).

Engine Oil Capacity Approx:

Refer to manual for specific year (typically around 0.8 - 1.0 Liter)

Fork Oil Type Recommendation:

Honda SS-7 or equivalent SAE 10W fork oil (refer to manual for exact specification and quantity).

Common Wear Items:

Clutch plates, carburetor jets, spark plugs, brake shoes, air filters, chain and sprockets, and fork seals.

Carburetor Issues:

Can become gummed up if not run regularly or if fuel quality is poor, leading to starting problems or poor running.

Electrical System Reliability:

While generally robust, older wiring can degrade, and rectifiers/regulators can fail over time. Ensure grounds are clean.

Clutch Slippage:

Wear on clutch plates can lead to slippage, especially under load. Requires adjustment and eventual replacement.

📚 Vehicle History

Honda Motorcycle Division Legacy:

Honda has a long and storied history in motorcycle manufacturing, known for reliability, innovation, and user-friendly designs, which is evident in the CT series.

Ct90 Predecessor Lineage:

The CT90 Trail 90 evolved from earlier Honda trail bikes, establishing Honda's reputation in the dual-purpose and off-road segments. It featured innovations like the 'True Dual Range' transmission on some models.

Ct110 Succession:

The CT110 Postie Bike was the successor to the CT90, building on its success and refining the design for increased utility and durability. It became particularly iconic in postal services worldwide.

Ct90 Production Period:

Initially produced from the mid-1960s, with significant updates leading into the CT110 era.

Ct110 Production Period:

Production spanned from the late 1970s through the early 2000s, making it a long-running and widely used model.

Market Recognition:

Both models are highly regarded for their ruggedness, simplicity, and ability to operate in diverse conditions, earning them legendary status.

🏆 Awards & Recognition

Model Iconic Status:

The CT110 Postie Bike is widely recognized as an iconic and dependable utility motorcycle, particularly in its association with postal services in countries like Australia and New Zealand.

Reliability Reputation:

Both models are renowned for their Honda reliability and longevity when properly maintained, making them highly sought after even today.