BSA · British unit twin (Triumph 350/500/650/750, BSA A50/A65 1957-1983)

C15 / B40 / B44 / B25 / B50 unit single

Library entry covers 1959-1973

17 factory 55 guideline

Published source

B.S.A. Workshop Manual for Models B44 Victor, C25 Barracuda, B44 Shooting Star (U.S.A.), B25 Starfire (U.S.A.), 1967 (B.S.A. Service Department)

Factory workshop manual. Covers 1967 (B44 Victor, B44 Shooting Star, C25 Barracuda, B25 Starfire).

Open the source

72 items for a 1959 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: Dry sump (separate oil tank)
Oil filtration: Mesh screens / strainers only
Valve gear: Overhead valve, pushrods, adjustable tappets
Ignition: Battery and coil with contact points
Charging: Alternator / stator with rectifier
Battery: Wet cell (flooded lead-acid, needs topping up)
Fuel system: Single carburetor
Cooling: Air / oil cooled
Primary drive: Chain in oil-bath case with its own oil
Gearbox oil: Separate gearbox oil
Clutch control: Hand lever, cable
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

1959 BSA C15 / B40 / B44 / B25 / B50 unit single

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

2 items

Check lights, horn, brake light switches

Pre-ride / on the road

Guideline
Check tire pressures

Pre-ride / on the road

Guideline

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

On the road: every 2,000 mi

1 item

Lubricate drive chain

Pre-ride / on the road

Factory

Manual: Lubricate rear chain. Factory: Every 2,000 miles (3,200 km), section A2.

Every 250 mi

1 item

Check battery electrolyte, top up with distilled water

Ignition and electrics

Factory

Manual: Battery: check electrolyte level, add distilled water. Factory: Weekly or every 250 miles, section G3.

Every 500 mi

1 item

Check primary chain oil supply (breather / pump feed)

Primary and gearbox

Factory

Manual: Check oil level in primary chaincase. Factory: Every 500 miles (800 km), section A2.

Every 1,000 mi or 1 month

1 item

Clean battery terminals, check charge and strap

Ignition and electrics

Factory

Manual: Battery: clean top, examine and clean terminals. Factory: Every 1,000 miles (1,600 km) or monthly, section G3.

Every 1,000 mi or 6 months

8 items

Check finned exhaust nuts / pipe clamps tight

Engine

Guideline
Inspect, clean and gap spark plugs

Engine

Guideline
Grease swingarm pivot

Rear suspension and frame

Guideline
Adjust front drum brake

Brakes

Guideline
Adjust rear drum brake and rod / cable linkage

Brakes

Guideline
Check spoke tension and wheel true

Wheels and tires

Guideline
Inspect tire tread, sidewalls and date codes

Wheels and tires

Guideline
Lubricate control cables and lever pivots

Controls and cables

Guideline

Every 1,500 mi or 6 months

2 items

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 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 1,500 mi or 12 months

1 item

Adjust clutch free play, lubricate cable and lever pivot

Primary and gearbox

Guideline

Every 2,000 mi or 12 months

1 item

Check / adjust primary chain

Primary and gearbox

Guideline

Every 2,000 mi

5 items

Change engine oil

Engine

Factory

Manual: Drain and refill the oil tank. Factory: Every 2,000 miles (3,200 km), section A2.
Clean oil strainers / mesh screens

Engine

Factory

Manual: Clean the oil filters; examine pump ball valve. Factory: Every 2,000 miles (3,200 km), section A2.
Check gearbox oil level

Primary and gearbox

Factory

Manual: Check oil level in gearbox. Factory: Every 2,000 miles (3,200 km), section A2.
Grease and check center / side stand and springs

Rear suspension and frame

Factory

Manual: Grease center stand, lubricate prop stand. Factory: Every 2,000 miles (3,200 km), section A2.
Lubricate brake cam spindles, check linings and drums

Brakes

Factory

Manual: Oil front / grease rear brake cam spindle. Factory: Every 2,000 miles (3,200 km), section A2.

Every 2,500 mi or 12 months

1 item

Check and adjust valve clearances

Engine

Guideline

Every 3,000 mi or 12 months

13 items

Check engine mounting bolts and plates

Engine

Guideline
Check pushrod tube seals and rocker box joints for leaks

Engine

Guideline
Check throttle cable(s) free play and return

Fuel and air

Guideline
Clean fuel tap filter / sediment bowl

Fuel and air

Guideline
Check / set ignition timing

Ignition and electrics

Guideline
Adjust clutch pushrod / clutch adjuster

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
Check wheel bearings for play

Wheels and tires

Guideline

Every 4,000 mi or 12 months

1 item

Replace spark plugs

Engine

Guideline

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

5 items

Clean and gap contact breaker points, oil cam felt

Ignition and electrics

Factory

Manual: Lubricate contact breaker cam. Factory: Every 5,000 miles (8,000 km), section A2.
Lubricate and check automatic advance unit

Ignition and electrics

Factory

Manual: Lubricate auto-advance mechanism. Factory: Every 5,000 miles (8,000 km), section A2.
Change gearbox oil

Primary and gearbox

Factory

Manual: Drain and refill gearbox. Factory: Every 5,000 miles (8,000 km), section A2.
Change primary chaincase oil

Primary and gearbox

Factory

Manual: Drain and refill primary chaincase. Factory: Every 5,000 miles (8,000 km), section A2.
Lubricate speedometer / tachometer cables, check drive

Controls and cables

Factory

Manual: Grease speedometer drive cable. Factory: Every 5,000 miles (8,000 km), section A2.

Every 6,000 mi or 12 months

4 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

Every 6,000 mi or 2 years

1 item

Check engine breather and oil return

Engine

Guideline

Every 10,000 mi or 2 years

1 item

Compression test (or leak-down)

Engine

Guideline

Every 10,000 mi

4 items

Replace chain and sprockets (wear based)

Final drive

Guideline
Change fork oil

Front end

Factory

Manual: Drain and refill front forks. Factory: Every 10,000 miles (16,000 km), section A2.
Repack / replace steering head bearings

Front end

Factory

Manual: Grease steering head bearings. Factory: Every 10,000 miles (16,000 km), section A2.
Repack / replace wheel bearings

Wheels and tires

Factory

Manual: Grease wheel bearings. Factory: Every 10,000 miles (16,000 km), section A2.

Every 12,000 mi or 3 years

1 item

Replace points and condenser

Ignition and electrics

Guideline

Every 12,000 mi or 4 years

1 item

Decarbonize head, grind / lap valves (top-end decoke)

Engine

Guideline

Period practice. Leaded-era valve seats may need hardened seats for unleaded fuel.

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 25,000 mi or 6 years

1 item

Replace swingarm bushes / bearings

Rear suspension and frame

Guideline

Every 25,000 mi

1 item

Clean crankshaft sludge trap (engine apart)

Engine

Guideline

Triumph and BSA twins trap sludge in the crank. Usually done at engine rebuild.

Every 30,000 mi or 6 years

1 item

Rebuild forks: seals, bushes, springs

Front end

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.