BSA · Two-stroke single, premix, chain drive

Bantam D1-D14 / B175

Library entry covers 1948-1971

17 factory 53 guideline

Published source

BSA Instruction Manual for D Models: D1 125cc Bantam, D3 and D5 150cc Bantam Major (B.S.A. Motor Cycles Ltd, MC.1360, Feb 1967 print; 2003 reproduction), Routine Maintenance p.9

Factory owner's handbook. Covers D1, D3, D5 (D-model instruction manual, 1967 print).

Open the source

70 items for a 1970 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: Two-stroke
Engine lubrication: Two-stroke premix (oil in fuel)
Oil filtration: None (no filter)
Valve gear: None (two-stroke porting)
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: 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

1970 BSA Bantam D1-D14 / B175

On the road: every 150 mi

1 item

Check two-stroke oil tank / carry premix oil

Pre-ride / on the road

Guideline

Running a two-stroke out of oil seizes it. Injection bikes: check the tank. Premix: carry oil and a measure.

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 1,000 mi

2 items

Check chain slack and rear wheel alignment

Pre-ride / on the road

Factory

Manual: Check rear chain adjustment. Factory: p.9.
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

Walk-around: check nuts and bolts for vibration loosening

Pre-ride / on the road

Factory

Manual: Check tightness of all nuts and bolts. Factory: p.9.

Every 300 mi

1 item

Check gearbox oil level

Primary and gearbox

Factory

Manual: Check oil level in gearbox. Factory: p.9.

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

10 items

Inspect, clean and gap spark plugs

Engine

Factory

Manual: Remove sparking plug for inspection. Factory: Ignition section text: every 1,000 mi (1,500 km) or so.
Clean / inspect air filter

Fuel and air

Factory

Manual: Air cleaner (oil-dip): dismantle, clean, re-oil. Factory: Carburetor section text: say every 1,000 mi (1,500 km).
Adjust clutch free play, lubricate cable and lever pivot

Primary and gearbox

Factory

Manual: Grease clutch operating mechanism. Factory: p.9.
Grease front forks (D1)

Front end

Factory

Factory: p.9; fork leg nipples, several strokes.
Grease steering head

Front end

Factory

Factory: p.9.
Grease and check center / side stand and springs

Rear suspension and frame

Factory

Manual: Grease central stand. Factory: p.9.
Grease plunger rear suspension, check springs and bushes

Rear suspension and frame

Factory

Manual: Grease rear suspension (plunger type). Factory: p.9.
Grease saddle pivot, check saddle springs / seat post

Rear suspension and frame

Factory

Manual: Oil saddle nose bolt. Factory: p.9.
Lubricate brake cam spindles, check linings and drums

Brakes

Factory

Manual: Oil brake cam spindles. Factory: p.9.
Repack / replace wheel bearings

Wheels and tires

Factory

Manual: Grease hubs. Factory: p.9.

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

Replace spark plugs (two-stroke)

Engine

Guideline
Grease swingarm pivot

Rear suspension and frame

Guideline
Lubricate control cables and lever pivots

Controls and cables

Guideline

Every 2,000 mi

2 items

Change gearbox oil

Primary and gearbox

Factory

Manual: Change the oil in the gearbox. Factory: p.9; gearbox also drained and flushed in running-in.
Lubricate speedometer / tachometer cables, check drive

Controls and cables

Factory

Manual: Grease the speedometer drive. Factory: p.9.

Every 3,000 mi or 12 months

13 items

Check engine mounting bolts and plates

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 spoke tension and wheel true

Wheels and tires

Guideline
Check wheel bearings for play

Wheels and tires

Guideline

Every 3,000 mi or 2 years

1 item

Decarbonize exhaust ports, pipes and baffles

Engine

Guideline

Two-strokes coke up the exhaust port and muffler baffles; power falls off gradually.

Every 3,000 mi

1 item

Clean and gap contact breaker points, oil cam felt

Ignition and electrics

Factory

Manual: Check contact breaker adjustment, grease felt pad. Factory: p.9 (Wipac section later says contacts and cam pad every 5,000 mi).

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 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

2 items

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 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

1 item

Repack / replace steering head bearings

Front end

Guideline

Many old machines use loose balls in cups and cones. Taper roller conversions are common.

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 1 month

1 item

Check battery electrolyte, top up with distilled water

Ignition and electrics

Factory

Manual: Monthly: examine battery and top up. Factory: p.9: monthly; more often in hot climate.

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.

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Factory

1962-1972

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