HOW TO REMOVE THE 250/300cc ENGINE

by Vic Locke (published in the Isetta Gazette December 1979)

1. Remove the two LOWER nuts and bolts from the silencer straps at the rear end of the silencer (Spanner size usually 10mm).

2. Remove 3 nuts holding exhaust pipe to cylinder head. (12mm ring spanner).

3. Pull exhaust pipe clear of the cylinder head.

4. Remove carburettor (2 x 14mm nuts) and air filter nozzle with curved rubber tube. (Remove air filter first. When you have removed the two carburettor nuts, pull the carb off of the studs and tie it up out of the way.) You do not need to remove either the throttle or choke cables, or the petrol feed pipe.

5. Remove casing around blower fan. (10mm spanner)

6. Remove blower fan complete with cam assembly. (Special tool needed)

7. Remove Dynastart field unit (4 cheesehead screws) and red starter cable, and the CB cable to coil. Ease the field unit off, and tie up out of the way. Pull H/T lead off of the sparking plug.

8. Remove the armature. (Special tool required). Some armatures are hard to get off, others easy. (They fit on the end of crankshaft taper/key.)

9. Remove the two LOWER engine mounting studs. They are the two studs that are screwed into each mounting, facing downwards. DO NOT disturb the UPPER engine mountings. Leave the lower engine mounts attached to the engine, otherwise, they will not go back into place when refitting.

10. Remove two lower nuts holding gearbox to engine. (14mm spanner).

11. Place wooden blocks under sump pan to take weight of engine when you pull it clear of the gearbox.

12. Remove two upper nuts holding gearbox to engine. (14mm spanner). Look carefully here, and make sure you don't undo the ones holding the steel engine mounting plates.

13. Then, facing the engine, gently rock it, and it should come clear of the gearbox, dropping onto the supporting blocks.

14. Lower the engine onto the ground.

I myself remove the dynastart unit from the engine so as to make the whole lot a little lighter for handling as I am usually alone for this job. If you wish to remove the engine complete, disconnect two wire connections under seat from the junction box and pull them through the bulkhead. Disconnect the starter cable on the Dynastart, CB cable on coil, and plug lead.. Disregard steps 5,6,7,8 above.

When replacing the engine, it has to be raised quite a lot for the four studs on the engine to line up with the holes in the gearbox flange. Once they are engaged, rotate the engine on the armature or blower fan to engage the clutch plate and gear box drive shaft.

Reverse procedure for refitting the engine in place. You will soon get the knack, once you have done it a few times. Let's hope you don't need to do it too often.