Vire 7 - Dismantling and Reassembly Instructions

Dismantling the Engine

Flywheel Removal

  1. Remove the V belt cover and the V belt
  2. Remove the fixing screws of the starting pulley and remove the pulley
  3. Using the special puller supplied, fit it to the flywheel with screws and tighten the puller centre screw against the end of the crankshaft
  4. Tap the head of the puller screw lightly with a hammer to loosen it. The flywheel should then be easily removed from the cone. Webmaster's Note: Take care not to lose the Woodruff key when removing the flywheel.

To Open the Crankcase

  1. Drain the oil from the reversing gearbox
  2. Remove the exhaust gas collector
  3. Remove the starter generator and the V belt cover
  4. Remove the flywheel as described above
  5. Remove the fixing screws of the reversing gearbox and separate it from the crankcase by use of a hide hammer. Do NOT force any hard tool between the flanges
  6. Remove the cylinder
  7. Remove the fixing screws between the two halves of the crankcase and separate the two halves
  8. Remove the crankshaft from the crankcase

Engine Assembly

Note: If the crankshaft is damaged, return it to the Manufacturer or to a Workshop recommended by the Manufacturer, to be repaired.

Oil lightly all the moving parts and shaft seals, paying particular attention to cleanliness.

The assembly is carried out in the following sequence:

  1. Assemble the bearings on the crankshaft and, using a suitable sleeve, tap against the inner ring of the bearing until it is in its correct position
  2. Assemble the shaft seals, taking care not to damage them
  3. Fit the crankshaft to the rear part of the crankcase, coat the sealing surfaces evenly with sealing compound and assemble the front part of the crankcase on the crankshaft, ensuring that the cylinder head joint surface is level
  4. Tighten the fixing screws
  5. Check the assembly of all parts installed so far by rotating the crankshaft
  6. Fit the piston assembly, ensuring that the piston ring grooves face the front (flywheel end) of the engine
  7. Assemble the cylinder and its gasket
  8. Assemble the magneto armature, flywheel and starting pulley
  9. Refit the reversing gearbox
  10. Assemble the starter generator, V belt, V belt cover, carburettor and exhaust gas collector

Mounting the Flywheel

  1. Assemble the flywheel on the crankshaft, ensuring that the Woodruff key enters the keyway provided
  2. Replace the nut on the flywheel and tighten it with a torque spanner (torque wrench) to 10 kpm. If a torque spanner is not available, adopt the following procedure:
    1. tighten the nut with a suitable socket wrench or box spanner as much as possible while holding the flywheel with the other hand
    2. tighten the nut 1/6 (one sixth) of a turn by tapping the end of the spanner with a hammer

If the fixing holes of the starting pulley do not line up with the corresponding holes in the flywheel, the nut must be tightened still further until the holes line up. The torque must never be reduced in order to effect the lining-up of the holes.

Dismantling the Reversing Gearbox

  1. Drain the oil from the reversing gearbox
  2. Separate the reversing gearbox from the engine as described above.
  3. Remove the water pump from the rear of the reversing gearbox by removing the housing fixing screws, then removing the case, impellor and gasket
  4. Using the impellor puller provided, remove the coupling flange
  5. Remove the shafts from the casing by pulling them forward. Use a hide hammer on the rear part of the shaft if difficulty is experienced
  6. Remove the gear lever (coupling rod) from the coupling crank by removing the elastic taper pin in the end of the shaft. When removing the gear lever, take care not to lose the spring and locating pin
  7. Remove the coupling crank from inside the gearbox
  8. The gear wheel of the reversing gear and its bearing can be removed by removing the locking ring from the shaft end
  9. Remove the bearings, taking care not to damage the cone surfaces and the splined shaft

Reassembling and Refitting the Reversing Gearbox

  1. Assemble the shaft seals
  2. Assemble the shaft bearings, using a sleeve of suitable diameter to apply pressure to the inner ring of the bearings
  3. Complete the main shaft assembly (cones, gear wheels, bearings and retaining rings)
  4. Assemble the main shaft bearings, using shims where necessary
  5. Refit the coupling crank and and refit the gear lever (coupling rod)
  6. Refit the shafts
  7. Refit the water pump assembly
  8. Assemble the sleeve, key and coupling flange on the external end of the main shaft
  9. Refit the reversing gearbox to the engine
  10. Check the endplay of the propellor shaft, which should be approximately 0.1 mm. If necessary, adjust with suitable adjusting shims
  11. Fill the reversing gearbox with gear oil

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