W/NG - Small Jobs

 A bit of workshop time this afternoon gave me the opportunity to complete some long-standing jobs on the W/NG.

This first is quite a simple one. There's been a leak from the rocker box oil feed for years - actually ever since I've had this bike. It's never had an acorn nut and in all the time I've been running it it's had a plain nut in this position which obviously won't seal the banjo. This afternoon I made a new acorn nut using a piece of suitable stainless steel hexagon bar finished with a specially ground form tool. 

Hopefully this will stop the leak!

Next up, a part that I didn't even know was missing until a chance post on the AOMCC forum. This little bit of bent sheet stops the field stand from moving upwards too far - it means that you can grab the stand with one hand whilst sitting on the bike and fit it neatly into its spring clips. Essentially the little bar guides the field stand into position and all you have to do is push it into the spring clip. 

It's made of a bit of 3 mm sheet, drilled for 7/16 and bent to shape.

Here it is, painted and in position.

Next is the new Lucas U39 switch - I have the proper one at last, including the 'T' position which illuminates only the tail lamp.

This is a picture of the underside of the existing switch, showing the position of all the wires.

I didn't get to finish this part of the job, so more of that later.

SQ4 - dodgy connections

 Riding home a couple of days ago in rather poor light I became aware that the headlamp had turned itself off. A few minutes fiddling with the light switch made me realise that there was something going on with the contacts - I could wiggle the handle and the light would flash. This needed further investigation.

As far as I could tell from various blog posts, this original Lucas U39 light switch had not been apart for probably 10 years. My own skills and knowledge have improved immensely in that time and I now clean these switches with an ammonia based clock cleaning solution as shown in this post. 

The one on the bike was clearly a bit grubby. 

I stripped it out and immersed it in a 25% solution of ammonia-based clock cleaner for about 4 hours.

After a few hours, the brass parts emerge without the tarnish and looking a lot more shiny and conductive!

Here it is again, reassembled.

Charlie’s Shed - Lucas U39 switch repairs

I’ve got a few Lucas U39 switches - in fact they are on most of the bikes. I have two on the bench at the moment, a civilian one from the FH and a military one destined for the W/NG, which has an extra position which illuminates the tail light only.

These notes are intended to record a few areas where these switches get damaged and to show ways they can be repaired. You’ll need a few simple tools and materials.

The first problem is the rotor - the part that fits in the knob is worn. It’s supposed to be a cylinder with two flats, but the flats are so worn & corroded that the knob wobbles about. What I’ve done here is make a fence around the shaft with sellotape and filled in the centre with JB Weld. It had previously been thoroughly cleaned with alcohol.

Here is a close up view of the finished rotor - I have used needle files to restore the shape of the flats fitting into the knob, being careful to ensure the pointer aligns with the text moulded into the top of the switch:

Next is a Bakelite repair, again with JB Weld. Someone has tried to prise the switch out of a panel with a screwdriver and broken the moulding in several places:

To fix these problems, the first thing to do is clean it all down with degreasers, brushes and scraping. I built a fence around the repair with some plastic card:

Removing the fence reveals hardened resin ready for shaping:

A short session with a flat file produces something we can paint:

Here we go. A little matt black U-Pol finished with a smear of silicone grease brings the Bakelite up nicely:

Next up, the contacts. Some of these switches have moving contacts operated by the rotor, which get corroded and full of muck. In this case, the spring had corroded away; to remove these contacts you have to withdraw a tiny split pin. I had to drill what remained of the split pin out with a 1 mm drill in a pin chuck. 

You can buy these torsion springs on eBay, but once you have made a few and perhaps have a few bits of piano wire lying around in various diameters it is easier to make your own.

The last job is to soak the brass parts in an ammonia based cleaner for a few hours. This removes all the tarnish:

FH - nacelle & handlebars

 I'm working on several fronts here, aiming to find problems and clear space so that I can start on the bottom end of the engine. Once that's in, there's polishing and plating, cables and wiring.

The nacelle went on relatively easily, though the trim on the front doesn't fit too well. That will need sorting out:

I planned to fit the instrument panel, mainly to avoid losing the trip reset cable but I found a few problems:

• the speedo bracket only fits one way, basically because it's too wide. I fitted it by elongating the holes but it would be nicer if I made a new one.
• the ammeter is one of those - - 0 - + ones, with no numbers. I'm not sure that's correct.
• the Lucas U39 headlamp switch is damaged where the clip fits - people prise these out and the Bakelite breaks.

On the up side, both the light switch and the speedometer have PVC cables - maybe the whole bike was wired using that stuff.

Next - working through the little bags of screws, I find the grub screw for the steering lock, so that's fitted:

I treated the bike to a nice set of stainless steel handlebars from Draganfly - made in Bungay. The SQ4 has these too and they are very nice.

There's a lot of work to bring the levers up to scratch though!

W/NG Wiring

As I received it, the W/NG has very little wiring remaining. This is the wiring diagram I will use, but it will need a brake light and a dip switch adding:

I've made a cable list showing destinations, colours, lengths & ratings:

I know that the W/NG used coloured cotton braided cable, because it is still there and there is no evidence of the rubber cable markers that the SQ4 wiring harness was fitted with. This must have changed during the war, as the W/NG workshop manuals show pictures of the headlamp instrument panel with banded wires.

Cotton covered cables. Wonder what colour they are?

I've bought some cotton braided cable from https://www.vintagecarparts.co.uk/. Looks fab:

Parcels still wrapped - more electrics

Well, the eBay parcels are still under wraps. Christmas is coming and sometimes it isn't wise to buy too many present for other women, however much shiny paint & chrome they will have when they are finished!

So in the meantime, let's get on with the headlamp. We've got a nice original SSU700, no repro bits here!

The instrument panel looks like it is off a WD bike; it's in great nick but the ammeter is wrong - it's not the white face one with the ignition light that should grace a Square Four headlamp.

Also, there are some flaky bits. The edges of the pilot light aperture are rather ragged - it's an aluminium casting and I'm not sure how to repair it yet. Then there is the rim:

The picture is not too hot but it's bent and it looks like it has been thrown down the road. I'm going to see if I can straighten it before I give up and buy a new one.

Here's the inside of the switch panel from the inside. All right & proper, apart from the ammeter I mentioned before. A new one will have to wait though - the proper ones will be like hens teeth!

Lighting switch, cleaned up nicely.

Here's the pilot light mounting plate. It was missing, but I made this one from some photos & dimensions provided from the fantastic people on the AOMCC forum. It's designed to hold one of these in the underslung pilot lamp:

And here is the ammeter, with the steering damper knob lurking in the background. I'm going to tackle the rim and the headlamp fasteners with a Plug 'n' Plate chrome plating kit, and see how much of the original stuff I can save.

More later.