Model A - primary chain case tinware

 Moving on from the clutch bowl, our 10 bashing activities come to the primary chain case. This is all present and mostly correct but some of the brackets and appendages have been broken and repaired by riveting. 

One thing we mustn't forget when we view this overall shot is that the position of the gearbox rather dictates the position of the primary case in that the primary case aperture for the clutch must accommodate the full range of movement of the gearbox. 

We must also think about the bolt hole for the rear upper chain guard. 

Again this position is dictated by something else - in this case the rear bolt for the chain guard which is fixed to the luggage carrier.

However we can take comfort from the fact that the holes for the foot rest bar, the brake lever and the shock absorber grease nipple at the front are fixed positions, so we can probably weld up the lower rear bracket without too much worry.

 The secondary cover, which protects the dynamo chain is present and in more or less sound condition - it's only missing one of the feet.

The stripped 1/4" CEI stud in this position came out very easily. The bracket is a little bent.

Here's that missing foot:

There's plenty to sort out here!

Model A - Lucas H52 headlamp

The Model A is fitted with a Lucas H52 headlamp which was sold to the industry between 1930 and 1932. It's distinctly different from the lamps that succeeded it as you will see. 

Outwardly the lamp fitted to my Model A looks a bit bashed, and indeed it is. The rim has obviously taken the brunt of a collision, but the nearside mounting is pushed right in as well.

The shell is brass, deeply drawn or spun - it's likely to be hard, so we may have to normalise it to avoid cracking.

To straighten out the front end requires adjusting the headlamp mounting bars and I can't do this with the headlamp bowl bent out of shape. In parallel with the clutch dome I have got out the panel beating hammers and dollies and set about straightening the bowl.

It's a little better in this shot but the near side mounting is still not positioned correctly. You can see the connections panel on the back of the switch here - the H52 has no internal wiring for the headlamp and side lamp but uses this Tufnol panel with sprung copper leaves for connection to the bulbs and ammeter.

Here is the inside of the main switch - it's retained to the Tufnol panel by two brass posts and sleeve nuts. You can see the half charge resistance and the switch in the middle. It's interesting that this switch is clearly a predecessor to the later commonly seen Lucas U39 switch, and you can see how it connects to the Tufnol connector panel from four of the terminal screws and from that central brass plate.

Here is the wiring diagram for the H52 - indeed for the whole bike. I suspect that since the headlamp is the centre of all things electrical, Lucas would have supplied the headlamp with the wiring for the whole bike already installed:

Here's the shell again with the nearside mounting almost correct. I think that to get it much better I will have to remove the rivets, straighten it and replace it with new rivets - these are round head copper rivets quite easily available.

There's also a flat on the shell around 2 o'clock.

The view from above shows that it is a bit better than before. We will need to buy a new rim and a new glass, but we will keep the old reflector. We will probably use one of the LED headlamp bulbs with an integral lens which doesn't use the reflector at all - I've got one of these on the W/NG and they're quite effective.

These bits are available from Jiri Horace at https://www.vintage-replica.com in the Czech Republic, so when we have a better handle what everything we could buy from him we will send an order.