Honda Trail 55 / Trail 90 / CT90 / CT110 — Example photo: Unknown author, CC BY-SA 4.0, Wikimedia Commons

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Honda · Honda trail (CT90 / CT110 / Trail 90 1964-1986)

Trail 55 / Trail 90 / CT90 / CT110

Library entry covers 1962-1986

70 factory 65 guideline

Published source

Honda CT90 Shop Manual 1966-76 and CT90/CT110 Shop Manual 1977-82 (archive.org scans, OCR text)

Factory workshop manual. Covers 1966-1982 (CT90 1966-76 manual; CT90 1977-79 / CT110 1980-82 shop manual).

135 items for a 1973 model, grouped by interval the way a factory chart is laid out.

How this bike is built (what the schedule is based on)

Engine cycle: Four-stroke
Engine lubrication: Wet sump (oil in crankcase)
Oil filtration: Centrifugal (slinger / rotor) filter
Valve gear: Overhead cam, screw/locknut adjusters
Ignition: Magneto (incl. magdyno, flywheel magneto)
Charging: Alternator / stator with rectifier
Battery: Wet cell (flooded lead-acid, needs topping up)
Fuel system: Single carburetor
Cooling: Air / oil cooled
Primary drive: Gear or chain inside engine, shares engine oil
Gearbox oil: Shares engine oil
Clutch control: Automatic or semi-automatic
Final drive: Chain
Front suspension: Telescopic fork
Rear suspension: Swingarm, twin shocks
Front brake: Drum (or band / stirrup)
Rear brake: Drum (or band / belt rim)
Wheels: Spoked, tubed
Sidecar: No sidecar

Maintenance schedule

1973 Honda Trail 55 / Trail 90 / CT90 / CT110

On the road: every 200 mi

1 item

Check engine oil level

Pre-ride / on the road

Guideline

Each fuel stop on old machines. Dry sump: check the tank hot, engine idling or just stopped, per your manual.

On the road: every 300 mi

3 items

Check lights, horn, brake light switches

Pre-ride / on the road

Guideline
Check tire pressures

Pre-ride / on the road

Guideline
Lubricate drive chain

Pre-ride / on the road

Guideline

Lube warm, ideally at the end of the riding day so it soaks in overnight. Sooner after rain.

On the road: every 500 mi

1 item

Walk-around: check nuts and bolts for vibration loosening

Pre-ride / on the road

Guideline

Old machines shake things loose: exhaust nuts, mudguard stays, footrests, tank mounts, battery strap.

On the road: every 600 mi

1 item

Check chain slack and rear wheel alignment

Pre-ride / on the road

Guideline

On the road: every 1,000 mi

1 item

Check road kit: plugs, points file, master link, tube patches, wire, tape

Pre-ride / on the road

Guideline

Every 300 mi

1 item

DRIVE CHAIN NOTE 3: I, L ('80 CT110 Addendum)

Final drive

Factory

Factory: As printed: I, L EVERY 300mi. (500km); NOTE 3 Service more frequently when riding OFF-ROAD.

Every 600 mi

1 item

DRIVE CHAIN NOTE (3): I ('78 1/2 Emissions Addendum)

Final drive

Factory

Factory: As printed: I EVERY 600mi. (1000km); NOTE (3) Initial service period 200 miles (300km).

Every 1,000 mi or 1 month

1 item

Check battery electrolyte, top up with distilled water

Ignition and electrics

Guideline

Wet-cell batteries on old machines need regular topping up, more in hot weather.

Every 1,000 mi or 6 months

3 items

Adjust front drum brake

Brakes

Guideline
Adjust rear drum brake and rod / cable linkage

Brakes

Guideline
Inspect tire tread, sidewalls and date codes

Wheels and tires

Guideline

Every 1,000 mi

4 items

Change engine oil

Engine

Factory

Manual: Engine oil change (1966-76). Factory: 1966-76 manual schedule: every 1,000 mi (1,600 km)
Check battery (1966-76)

Ignition and electrics

Factory

Factory: As printed: diamond at every column from 300 mile (500 km) to 12,000 mile (18,000 km)
Drive chain inspection (1966-76)

Final drive

Factory

Factory: 1966-76 manual text: inspect drive chain every 1,500 km (1,000 mi)
Adjust front and rear brakes (1966-76)

Brakes

Factory

Factory: As printed: diamond at every column from 1,000 mile (1,500 km) to 12,000 mile (18,000 km)

Every 1,200 mi or 12 months

1 item

Engine oil replace (1978 CT90 emissions schedule)

Engine

Factory

Factory: hondact90ct110manual p.113: replace every year or 1,200 mi (2,000 km)

Every 1,250 mi

1 item

Engine oil replace (1980-82 CT110 schedule)

Engine

Factory

Factory: hondact90ct110manual CT110 schedule: replace every 1,250 mi (2,000 km), OCR

Every 1,500 mi or 6 months

1 item

Clean drive chain thoroughly (remove and soak, re-lube)

Final drive

Guideline

Non O-ring chains on old machines: remove, clean, soak in hot chain grease or lube, refit with the master link clip closed end leading.

Every 2,000 mi or 12 months

3 items

Inspect, clean and gap spark plugs

Engine

Guideline
Grease swingarm pivot

Rear suspension and frame

Guideline
Lubricate control cables and lever pivots

Controls and cables

Guideline

Every 2,400 mi or 1 month

1 item

BATTERY: I ('78 1/2 Emissions Addendum)

Ignition and electrics

Factory

Factory: As printed: EVERY MONTH; I at 600mi. (1000km), 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)

Every 2,400 mi

21 items

* HEADLIGHT AIM: I ('78 1/2 Emissions Addendum)

Engine

Factory

Factory: As printed: I at 600mi. (1000km), 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)
* NUTS, BOLTS, FASTENERS: I ('78 1/2 Emissions Addendum)

Engine

Factory

Factory: As printed: I at 600mi. (1000km), 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)
* SPARK ARRESTER: C ('78 1/2 Emissions Addendum)

Engine

Factory

Factory: As printed: C at 2400mi., 4800mi., 7200mi.
* STOP LIGHT SWITCH: I ('78 1/2 Emissions Addendum)

Engine

Factory

Factory: As printed: I at 600mi. (1000km), 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)
* SUSPENSION: I ('78 1/2 Emissions Addendum)

Engine

Factory

Factory: As printed: I at 600mi. (1000km), 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)
* THROTTLE OPERATION: I ('78 1/2 Emissions Addendum)

Engine

Factory

Factory: As printed: I at 600mi. (1000km), 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)
* VALVE CLEARANCE: I ('78 1/2 Emissions Addendum)

Engine

Factory

Factory: As printed: I at 600mi. (1000km), 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)
CRANKCASE BREATHER NOTE (1): C ('78 1/2 Emissions Addendum)

Engine

Factory

Factory: As printed: C at 2400mi., 4800mi., 7200mi.; NOTE (1) More frequent service may be required when riding in rain or at full throttle openings. (U.S.A. only)
SPARK PLUG: I ('78 1/2 Emissions Addendum)

Engine

Factory

Factory: As printed: I at 2400mi. (4000km) and 4800mi. (8000km)
* CARBURETOR CHOKE: I ('78 1/2 Emissions Addendum)

Fuel and air

Factory

Factory: As printed: I at 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)
* CARBURETOR IDLE SPEED: I ('78 1/2 Emissions Addendum)

Fuel and air

Factory

Factory: As printed: I at 600mi. (1000km), 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)
* FUEL LINES: I ('78 1/2 Emissions Addendum)

Fuel and air

Factory

Factory: As printed: I at 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)
AIR CLEANER NOTE (2): C ('78 1/2 Emissions Addendum)

Fuel and air

Factory

Factory: As printed: C at 2400mi., 4800mi., 7200mi.; NOTE (2) More frequent service may be required when riding in dusty areas.
* CONTACT BREAKER POINTS: I ('78 1/2 Emissions Addendum)

Ignition and electrics

Factory

Factory: As printed: I at 600mi. (1000km), 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)
* IGNITION TIMING: I ('78 1/2 Emissions Addendum)

Ignition and electrics

Factory

Factory: As printed: I at 600mi. (1000km), 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)
CLUTCH FREE PLAY: I ('78 1/2 Emissions Addendum)

Primary and gearbox

Factory

Factory: As printed: I at 600mi. (1000km), 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)
* CAM CHAIN TENSION: A ('78 1/2 Emissions Addendum)

Final drive

Factory

Factory: As printed: A at 600mi. (1000km), 2400mi., 4800mi., 7200mi.
SIDE STAND: I ('78 1/2 Emissions Addendum)

Rear suspension and frame

Factory

Factory: As printed: I at 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)
BRAKE SHOE WEAR: I ('78 1/2 Emissions Addendum)

Brakes

Factory

Factory: As printed: I at 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)
BRAKE SYSTEM: I ('78 1/2 Emissions Addendum)

Brakes

Factory

Factory: As printed: I at 600mi. (1000km), 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)
** WHEELS: I ('78 1/2 Emissions Addendum)

Wheels and tires

Factory

Factory: As printed: I at 600mi. (1000km), 2400mi. (4000km), 4800mi. (8000km), 7200mi. (12000km)

Every 2,500 mi or 1 month

1 item

BATTERY: I ('80 CT110 Addendum)

Ignition and electrics

Factory

Factory: As printed: EVERY MONTH; I at 600mi. (1,000km), 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km)

Every 2,500 mi

21 items

**SPARK ARRESTER (USA only): C ('80 CT110 Addendum)

Engine

Factory

Factory: As printed: C at 2,500mi., 5,000mi., 7,500mi.
*HEADLIGHT AIM: I ('80 CT110 Addendum)

Engine

Factory

Factory: As printed: I at 600mi. (1,000km), 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km)
*NUTS, BOLTS, FASTENERS NOTE 3: I ('80 CT110 Addendum)

Engine

Factory

Factory: As printed: I at 600mi. (1,000km), 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km); NOTE 3 Service more frequently when riding OFF-ROAD.
*SUSPENSION: I ('80 CT110 Addendum)

Engine

Factory

Factory: As printed: I at 600mi. (1,000km), 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km)
*THROTTLE OPERATION: I ('80 CT110 Addendum)

Engine

Factory

Factory: As printed: I at 600mi. (1,000km), 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km)
*VALVE CLEARANCE: I ('80 CT110 Addendum)

Engine

Factory

Factory: As printed: I at 600mi. (1,000km), 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km)
CRANKCASE BREATHER (USA only) NOTE 2: C ('80 CT110 Addendum)

Engine

Factory

Factory: As printed: C at 2,500mi., 5,000mi., 7,500mi.; NOTE 2 Service more frequently when riding in rain or at full throttle. (USA ONLY)
SPARK PLUG: R ('80 CT110 Addendum)

Engine

Factory

Factory: As printed: R at 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km)
*CARBURETOR-CHOKE: I ('80 CT110 Addendum)

Fuel and air

Factory

Factory: As printed: I at 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km)
*CARBURETOR-IDLE SPEED: I ('80 CT110 Addendum)

Fuel and air

Factory

Factory: As printed: I at 600mi. (1,000km), 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km)
*FUEL LINE: I ('80 CT110 Addendum)

Fuel and air

Factory

Factory: As printed: I at 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km)
AIR CLEANER NOTE 1: C ('80 CT110 Addendum)

Fuel and air

Factory

Factory: As printed: C at 2,500mi., 5,000mi., 7,500mi.; NOTE 1 Service more frequently when riding in dusty areas.
*CONTACT BREAKER POINTS: I ('80 CT110 Addendum)

Ignition and electrics

Factory

Factory: As printed: I at 600mi., 2,500mi., 7,500mi.; R at 5,000mi. (8,000km)
*IGNITION TIMING: I ('80 CT110 Addendum)

Ignition and electrics

Factory

Factory: As printed: I at 600mi. (1,000km), 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km)
CLUTCH: I ('80 CT110 Addendum)

Primary and gearbox

Factory

Factory: As printed: I at 600mi. (1,000km), 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km)
*CAM CHAIN TENSION: A ('80 CT110 Addendum)

Final drive

Factory

Factory: As printed: A at 600mi., 2,500mi., 5,000mi., 7,500mi.
SIDE STAND: I ('80 CT110 Addendum)

Rear suspension and frame

Factory

Factory: As printed: I at 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km)
*BRAKE LIGHT SWITCH: I ('80 CT110 Addendum)

Brakes

Factory

Factory: As printed: I at 600mi. (1,000km), 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km)
BRAKE SHOE WEAR: I ('80 CT110 Addendum)

Brakes

Factory

Factory: As printed: I at 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km)
BRAKE SYSTEM: I ('80 CT110 Addendum)

Brakes

Factory

Factory: As printed: I at 600mi. (1,000km), 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km)
**WHEELS/SPOKES NOTE 3: I ('80 CT110 Addendum)

Wheels and tires

Factory

Factory: As printed: I at 600mi. (1,000km), 2,500mi. (4,000km), 5,000mi. (8,000km), 7,500mi. (12,000km); NOTE 3 Service more frequently when riding OFF-ROAD.

Every 3,000 mi or 12 months

18 items

Check and adjust valve clearances

Engine

Guideline
Check engine mounting bolts and plates

Engine

Guideline
Clean oil strainers / mesh screens

Engine

Guideline

Often done with every oil change on old machines.
Check throttle cable(s) free play and return

Fuel and air

Guideline
Clean / inspect air filter

Fuel and air

Guideline

Mesh or oiled foam: clean and re-oil. Paper: blow out or replace. Some very early machines have no filter at all.
Clean fuel tap filter / sediment bowl

Fuel and air

Guideline
Check / set ignition timing

Ignition and electrics

Guideline
Clean and gap contact breaker points, oil cam felt

Ignition and electrics

Guideline
Adjust automatic / semi-automatic clutch

Primary and gearbox

Guideline
Check chain guard, chain oiler (if fitted), rear chain case

Final drive

Guideline
Inspect chain and sprockets for wear (measure stretch)

Final drive

Guideline
Check steering damper (friction or hydraulic)

Front end

Guideline
Check steering head bearing adjustment

Front end

Guideline
Inspect fork seals, stanchions and fork boots

Front end

Guideline
Check footrests, pegs, rear brake and gear lever pivots

Rear suspension and frame

Guideline
Grease and check center / side stand and springs

Rear suspension and frame

Guideline
Check spoke tension and wheel true

Wheels and tires

Guideline
Check wheel bearings for play

Wheels and tires

Guideline

Every 3,000 mi

8 items

Adjust valve clearance (1966-76)

Engine

Factory

Factory: As printed: diamond at 300 mile (500 km), then 3,000 / 6,000 / 9,000 / 12,000 mile
Adjusting lighting equipment and horn (1966-76)

Engine

Factory

Factory: As printed: diamond at 3,000 / 6,000 / 9,000 / 12,000 mile (4,500 / 9,000 / 13,500 / 18,000 km)
Clean spark plug (1966-76)

Engine

Factory

Factory: As printed: diamond at 3,000 / 6,000 / 9,000 / 12,000 mile (4,500 / 9,000 / 13,500 / 18,000 km)
Adjust carburetor (1966-76)

Fuel and air

Factory

Factory: As printed: diamond at 3,000 / 6,000 / 9,000 / 12,000 mile (4,500 / 9,000 / 13,500 / 18,000 km)
Clean air cleaner (1966-76)

Fuel and air

Factory

Factory: As printed: diamond at 3,000 / 6,000 / 9,000 / 12,000 mile (4,500 / 9,000 / 13,500 / 18,000 km)
Clean fuel strainer (1966-76)

Fuel and air

Factory

Factory: As printed: diamond at 3,000 / 6,000 / 9,000 / 12,000 mile (4,500 / 9,000 / 13,500 / 18,000 km)
Adjust ignition timing (1966-76)

Ignition and electrics

Factory

Factory: As printed: diamond at 3,000 / 6,000 / 9,000 / 12,000 mile (4,500 / 9,000 / 13,500 / 18,000 km)
Adjust clutch (1966-76)

Primary and gearbox

Factory

Factory: As printed: diamond at 1,000 mile (1,500 km), then 3,000 / 6,000 / 9,000 / 12,000 mile

Every 4,000 mi or 12 months

2 items

Replace spark plugs

Engine

Guideline
Lubricate brake cam spindles, check linings and drums

Brakes

Guideline

Every 4,800 mi

1 item

* ENGINE OIL FILTER SCREEN: C ('78 1/2 Emissions Addendum)

Engine

Factory

Factory: As printed: C at 4800mi. (8000km)

Every 5,000 mi or 2 years

1 item

Check cylinder head bolt torque

Engine

Guideline

Air-cooled iron and alloy engines can lose head bolt tension; follow your manual's sequence and whether it is done hot or cold.

Every 5,000 mi

2 items

*ENGINE OIL FILTER SCREEN: C ('80 CT110 Addendum)

Engine

Factory

Factory: As printed: C at 5,000mi. (8,000km)
*CONTACT BREAKER POINTS: R ('80 CT110 Addendum)

Ignition and electrics

Factory

Factory: As printed: R at 5,000mi. (8,000km)

Every 6,000 mi or 12 months

5 items

Clean carburetor float bowl(s), check float level and jets

Fuel and air

Guideline

Ethanol fuel varnishes old carbs quickly in storage.
Check charging voltage and regulator / cut-out

Ignition and electrics

Guideline
Check swingarm bushes for play

Rear suspension and frame

Guideline
Inspect rear shocks for leaks and damping

Rear suspension and frame

Guideline
Lubricate speedometer / tachometer cables, check drive

Controls and cables

Guideline

A dry speedo cable whips the needle and eventually kills the instrument.

Every 6,000 mi or 2 years

4 items

Check engine breather and oil return

Engine

Guideline
Clean centrifugal oil filter (rotor / slinger)

Engine

Guideline
Lubricate and check automatic advance unit

Ignition and electrics

Guideline
Magneto: clean slip ring and pickup brush, check HT lead

Ignition and electrics

Guideline

Every 6,000 mi

4 items

Clean muffler (1966-76)

Engine

Factory

Factory: As printed: diamond at 6,000 and 12,000 mile (9,000 and 18,000 km)
Clean oil filter (1966-76)

Engine

Factory

Factory: As printed: diamond at 300 mile (500 km), then 6,000 and 12,000 mile (9,000 and 18,000 km)
Retighten nuts and bolts (1966-76)

Engine

Factory

Factory: As printed: diamond at 1,000 mile (1,500 km), then 6,000 and 12,000 mile (9,000 and 18,000 km)
Check tightness of spokes (1966-76)

Wheels and tires

Factory

Factory: As printed: diamond at 1,000 mile (1,500 km), then 6,000 and 12,000 mile (9,000 and 18,000 km)

Every 7,200 mi

2 items

SPARK PLUG: R ('78 1/2 Emissions Addendum)

Engine

Factory

Factory: As printed: R at 7200mi. (12000km)
** STEERING HEAD BEARING: I ('78 1/2 Emissions Addendum)

Front end

Factory

Factory: As printed: I at 600mi. (1000km) and 7200mi. (12000km)

Every 7,500 mi

1 item

**STEERING HEAD BEARING: I ('80 CT110 Addendum)

Front end

Factory

Factory: As printed: I at 600mi. (1,000km) and 7,500mi. (12,000km)

Every 10,000 mi or 2 years

2 items

Compression test (or leak-down)

Engine

Guideline
Change fork oil

Front end

Guideline

Some early telescopic forks are grease filled or use very small oil quantities. Check your manual.

Every 10,000 mi

1 item

Replace chain and sprockets (wear based)

Final drive

Guideline

Every 12,000 mi or 2 years

1 item

Replace air filter element

Fuel and air

Guideline

Every 12,000 mi or 3 years

1 item

Replace points and condenser

Ignition and electrics

Guideline

Every 15,000 mi or 5 years

1 item

Inspect clutch plates and springs

Primary and gearbox

Guideline

Every 15,000 mi

1 item

Replace brake linings / skim drums (wear based)

Brakes

Guideline

Every 20,000 mi or 4 years

2 items

Repack / replace steering head bearings

Front end

Guideline

Many old machines use loose balls in cups and cones. Taper roller conversions are common.
Repack / replace wheel bearings

Wheels and tires

Guideline

Cup-and-cone and taper roller hubs need periodic repacking and adjustment.

Every 25,000 mi or 6 years

1 item

Replace swingarm bushes / bearings

Rear suspension and frame

Guideline

Every 25,000 mi or 10 years

1 item

Magneto overhaul / re-magnetize, replace capacitor

Ignition and electrics

Guideline

Weak spark when hot is the classic symptom. Old capacitors fail with age, not miles.

Every 30,000 mi or 6 years

1 item

Rebuild forks: seals, bushes, springs

Front end

Guideline

Every 6 months

1 item

Clean battery terminals, check charge and strap

Ignition and electrics

Guideline

Every 12 months

1 item

Check speedometer / odometer against a known distance

Controls and cables

Guideline

Old speedos drift with tire size and drive wear. Use phone GPS over a measured 10 miles / km.

Every 2 years

3 items

Inspect fuel tank for rust, sealer failure, leaks

Fuel and air

Guideline
Inspect wiring, bullet connectors and ground points

Ignition and electrics

Guideline
Inspect frame, welds and lugs for cracks

Rear suspension and frame

Guideline

Every 4 years

1 item

Replace fuel lines

Fuel and air

Guideline

Old rubber and modern ethanol fuel do not mix well.

Every 6 years

2 items

Replace inner tubes and rim tape with tires

Wheels and tires

Guideline
Replace tires on age (regardless of tread)

Wheels and tires

Guideline

Guideline lines: Intervals here are general guidelines for the machine's era and layout, compiled for this app. They are not factory manual figures. Check your workshop manual, and edit any interval in the bike's Schedule tab.