Removing the Carburettor

  1. Remove the split pin on ball joint linkage and loosen.
  2. Loosen petrol pipe at float bowl.
  3. Remove four nuts securing carburettor to inlet manifold.
  4. Remove carburettor.
Carburettor Measurements
  • Float (70mm)
  • OD Float Chamber 78mm

Removing the Valves

  1. The bonnet must be removed to facilitate the removal of the valves.
  2. Remove spark plugs/compression taps and blanking plugs from the valve caps.
  3. Place valve cap spanner in top of valve cap, get someone to stand on it and loosen the valve cap.
  4. Remove valve cap.
  5. Remove push rod assembly and stuff the hole with a rag to prevent things from ending up in the engine.
  6. Use valve spring compressors to compress the spring then remove securing clip.
  7. Remove tool
  8. Push up the valve and remove it through the valve cap hole.

Grinding in the Valves

  1. Start with the procedure used to remove the valve (see above).
  2. Apply a little grinding paste around the valves seating face (four small pieces around the valve seems to work)
  3. Return valve to cylinder block.
  4. Work the valve around 40-degree side to side with a screwdriver in the slot on the top of the valve.
  5. As you feel the paste is becoming blunt remove the valve, wipe off the seat and renew the paste
  6. Repeat this process until you can see a sealing ring all the way around the valve and seat.
  7. Thoroughly wipe the valve and seat until you are sure no paste remains
  8. Reassemble.

Removing the Inlet Manifold

  1. Remove carburettor (see above).
  2. Remove nuts on either end of the two water pipes to give room to remove the manifold.
  3. Remove four nuts securing the manifold to the two cylinder blocks.
  4. Remove manifold.

Removing the Cylinder Blocks (Pots)

See page on Removing the Cylinder Blocks.

Removing a Conrod

  1. Position the cylinder at bottom dead centre.
  2. Remove the split pins on the big end bolts.
  3. Loosen the nuts. The bolts should have a reaction force applied with an allen key while the nuts are removed using a 1/2W socket and the breaker bar. Apply force such that you are not trying to turn the crakshaft.
  4. Remove the nuts and washers (keeping orientation) holding the big end together.
  5. Remove lower bearing shell, support and spacers keeping the orientation of each.
  6. Remove the con rod and upper bearing shell (keeping orientation). Reassemble conrod, bearing etc. so that alignment is kept.

Reassembly is the reversal of removal.

Machining a Little End Bush

See page on Machining a Little End Bush.

Removing the Sump

See page on Removing the Sump.

Removing the Timing Case Cover

  1. Unbolt fan assembly at the timing case.
  2. Unbolt fan belt pulley. This has a lock nut and is in two parts to facilitate its removal past the sub-chassis.
  3. Unbolt starting handle boss and all the other bolts going through the two halves of the timing case.
  4. Remove cover.

Removing the Timing Gears

  1. Remove the brass plugs on the back of the timing case.
  2. Mark alignment of gears to ensure correct reassembly.
  3. Loosen the camshaft nut in the centre of the gear about 1/8″ but do not remove.
  4. Use timing gear puller by bolting it through the holes in the timing gear and applying torque to the centre threaded section of the camshaft.
  5. Shock the taper fit using an aluminium drift against the end of the taper. The gear should spring off.
  6. Remove the gear carefully making sure the key (or its orientation) is not lost.

Exhaust Technical Details

  • 2″ OD
  • 2mm Wall thickness
  • Lengths beyond silencer: 2′ straight, 2′ Radius, 2′ straight