Session 5: Gear Selector Part 2

Right, continuing from the previous post, we will dig down to the gearbox, and remove the selector, which we need to replace.

5. Remove kickstart spring

The spring and washer from the kickstart

Twist off the spring and tab washer, but be careful in case it is under any tension.





6. Remove camplate spindle

The spindle and split pin

Remove this plate.

On pre-1965 engines, there is a small rectangular plate, with a cork gasket. Undo the two screws, and remove the plate. Then, pull out the split pin, and remove the camplate spindle from the left hand side.



7. Remove camshaft nut

The nut and washers. The two washers fit
 into each other, as shown. 

If you can get the bike into gear, it is much easier to remove the nut, as the shaft cannot turn so easily. Take off the nut, and two washers, one on the other. Be careful, as trying to remove this nut can cause the piston to move, so if it isn't free, be careful of causing damage.




8. Undo screws

The different lengths of screw. 

Undo all the crosshead screws, to release the inner gearbox cover. There is one screw, which should have a flat head, next to the kickstart shaft, which should be left alone. Again, I could recommend ensuring you know where they came from, as they are different lengths.




9.Remove inner gearbox cover

Ready to remove the inner
gearbox cover. 

The inner gearbox cover should now be ready to remove. We found that it was catching on the frame of the bike, so we unscrewed a couple of engine mounting bolts, and lifted the engine slightly. You may find that whatever was used to make a seal around the join is holding the cover on. Carefully use a block of wood and a hammer to gently tap the side of the casing, making sure not to directly hit the aluminium with the hammer. the cover should then lift off.

The gearbox. 

10. Remove gear selector shaft

The gear selector shaft. 

There is a bolt below the gear selector shaft, which when undone, allows the shaft to be easily removed.




I will now try and find a supplier of BSA parts, to buy a new shaft, as this one has been drilled and ruined. This may take some time, so I will probably go back to doing other jobs, or start painting for the next session.

Some pictures from the inside of the gearbox:

The kickstart, bottom, and gears above it. 

Timing gear.