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. 

Session 4: Gear Selector Part 1

As previously mentioned, the gear selector shaft needs replacing, to rectify repairs Dad made to keep it going in the past. The splines on the end which hold the lever on wore off, so he drilled through the shaft and bolted the lever on. Here is how to go about getting to the gears, and changing the shaft.

1. Remove oil

The drain plug, on the underside of the gearbox.
Note the bolt, in the centre of a larger bolt. 

There is a double bolt on the bottom of the gearbox. the inside of it has a long rod, which shows the oil level, and the outside is a drain plug. The little book we have has an interesting fact, that pre-1965 engines like this had the gauge wrong on the bolt. According to the book, an extra 1/4 of a pint should be added once the gauge is full. Engines built after 1965 had a corrected gauge. When I removed the bolt on ours, no oil came out, as we expected.



2. Remove levers

The two levers, kickstart on the left,
and the gear selector on the right. 

The kickstart lever, and gear selector need to be removed, before the cover can come off. The kickstart has a cotter pin, so undo the nut, and knock the pin out. The lever should then come off. The gear selector should have a splined end and clamp holding it on . On this bike, many years ago, Dad drilled it out, and there is just a standard nut and bolt. The shaft and selector need replacing, so we can return it to how it originally was.

After the levers have been removed. 

3. Remove exhaust

The bike sans exhaust. 

Taking the exhaust off is very easy, by removing two bolts. One bolt is the right hand passenger foot peg, bolting the muffler to the frame. When removing it, remember which way the bolt turns, as it is the other way over. It is common sense, but it's very annoying if you try the wrong way. The other bolt is at the front, bolting the pipe to the frame. The driver right footpeg needs turning, by loosening the bolt on the back, and turning it until it is out of the way. Once you have removed the bolts, and turned the footrest, the exhaust should rotate and lift off.

The exhaust, full of horrible powdery dust. 

I found the exhaust was full of powdery dust. Don't worry too much if some goes into the hole in the engine, because it will be blown out when you start it, but it may be a good idea just to knock it out.



4. Undo bolts

My drawing, showing the bolts. The view is as
you face the right hand side of the engine. 

The gearbox outer cover is held on with a bizarre assortment of bolts, around the outside. Dad bought a set of allen head bolts for it, which are currently fitted, but we still have the original bolts somewhere. Simply remove the bolts, and lift the cover off. I used a crude drawing to make sure I knew where the bolts went.

The cover, after removal. 

The kickstart assembly.

The pictures to each side show how it should look at this step. The engine is pre 1965, so later engines may look slightly different.




I will continue the disassembly, removal and reassembly in a day or two, when I have more time. On a totally unrelated note, I wrote to the BSA owners club last week, so they will hopefully send me the original manufacturing records. The records should state the original colour, so I know what to paint it.