SQ4 - all done

This might be the last post on the Square Four for a little while - it's next trip is likely to be to my long-term storage at my son's house, where I shall go to collect W/NG to come back for some work - but more on that later .

Today I took the Square on a 15 mile round trip to Cromer to do some painting and do the final shake down on the carburettor and ignition settings. Yesterday I fitted the new mixture screw and this needed a little bit of tweaking to get it spot on and I increase the idle speed slightly - though I think I've got it too high. I also retarded the ignition slightly. 

The good news is that it's running very well. It starts easily and it will pull away cleanly in traffic from low speeds. It flies along on the open road so all in all I'm very happy.

Here it is resting at Gresham church.

Getting home, it occurred to me that in a similar fashion to the light switch yesterday I had not touched the horn for a long time. Since I fitted this horn, which came straight from eBay, I don't think it's had any work done to it and as regular readers will know I've become reasonably adept at adjusting these horns.

I gave this one a little tweak to make the sound a bit more intense.

W/NG horn repair

The W/NG has had a rather nice military Altette for years, which I found I think on eBay. It's always worked, but never very well - not very loud and with that strangled parrot sound common to Altettes with shims missing or loose parts.

One idle moment I tinkered around with the adjuster, which is quite easy to get to in these early Altettes being hidden under a big cap nut on the front of the horn. I could get it to sound a bit better, but I was puzzled by the adjuster moving out of position after I had tightened it. I realised eventually that the armature, which is held to the diaphragm by a large nut and which contains the adjuster, was loose on the diaphragm.

No matter! Says I, I will tighten it up. Weeks of soaking in various solvents followed as these are notoriously tight and being out in the weather, will corrode up. I eventually loosened it with a big tube spanner, only to find that it wasn't loose on the diaphragm at all but that there was a nice ring of diaphragm material held tightly by the nut but that was no longer attached to the rest of the diaphragm. A fatigue failure after 80 years of service!

Now, you can't buy these parts. I had another Altette to cannibalize, but I also have a TIG welder. After a few attempts (during which time I realised my Tungsten tip was contaminated, hence the mess on the left) I got a decent weld all around and re-fixed the broken ring in its original position.

The Dremel made short work of the excess weld:

In adjusting the horn, I was messing about with the screws on the back. It's important that the internal contact breaker assembly is level:

The two screws on the right fix the contact breaker; the one on the left adjusts the level. Once you have it level, leave the screw alone!

Here's the diaphragm reassembled with the armature and the adjuster. I assembled the rest of the horn and tested it - it didn't work, but the coiled pulled the armature in. Why? Because the diaphragm is upside down in this picture...

With it turned over, it worked beautifully and sounded better than it ever has.

Altette

Nice ex-WD, period Lucas Altette for the W/NG:

Just needs the right brackets, like this one:

Which looks like this when it has been beaten into submission, painted and installed:

Here's the horn bracket fitted:

...and here is the horn in place. A very tight fit indeed:

Fill in jobs...

This is an original Lucas Altette, bought from eBay for the Ariel. Apart from one stripped thread and non-original acorn nut, it is perfect.

It came with the right angle bracket, an original Lucas one, that is used on the earlier machines with the smaller battery. Since Amelia should have the big 20 Amphour battery, we will use the straight bracket shown attached to the horn. I bought this from Vintage Bike & it looks like a nice quality part.