SQ4 - a little investigation

 Of course, a broken motorcycle can’t be left for too long, especially when your daily rider has been persuaded from your grasp.

There were a few problems to investigate, possibly associated:

• There was a carburetter leak, or possibly flooding 
• The battery indicator was showing far too much red, considering the 60 miles the bike traveled yesterday 
• The bike refused to start twice yesterday, needing pushing to the top of a hill and roll-starting 

Putting the CTEK on the battery had it charging normally, but it was very flat:

But why so flat? According to the ammeter, the battery does charge and indeed, it was charging on the way home. I did notice the ignition had been left on as Tom had complained the engine wouldn’t idle and it had died when he arrived. I currently believe this has more to do with the battery than anything else.

There is no leakage from the battery with the engine not running and you can measure normal currents with lights on, though with the LEDs fitted to this bike these are minimal. The ignition circuit draws 400 mA without the engine running - I think it would be a good idea to try this with the engine running.

I've also realised that the red spot ammeter doesn't show very much deflection at all - I calibrated the one on the Huntmaster against my bench power supply and there is a lot more movement. I wonder if the Square Four has a 30-0-30 ammeter.

A simple test with a 35 watt bulb revealed that the ammeter appears to be 15-0-15 - while I was doing this test the multimeter was reading 5 amps.

As a first step towards sorting the fuel leak, I removed the drain plug/main jet holder and finding no new fibre washer of the right size, sealed it with a wipe of Threebond 1215. That fixed the leak, and there is no evidence of flooding. 

Amelia started first time like she always does.

As to the idle, I don’t know yet as I haven’t got it warm enough to close the bi-starter.

Ammeter Finished

So, here is the finished article. The ammeter has been stripped & cleaned inside & out and is now working happily.

The chrome on the rim is good, and the case has been repaired.

This is the new ignition light. The design & material selection is inspired from the genuine ones I have seen on eBay and the various forums, particularly the C10/C11/C12 forum. It's not an exact replica of anything but it looks the part.

I've made a carrier from 2 mm Tufnol which is a little thick, but all I had. The lamp bracket is made from 0.5 mm brass sheet, with insulation gaskets as necessary, riveted together. The one thing I would like to find now are a couple of 2 BA thumb nuts to replace those steel hex nuts.

Almost a red spot ammeter

Well, here is the first of the post-Christmas presents!

This is the kit of parts that I have, now that I have stripped a Lucas red spot ammeter that I bought on eBay from a member of the AOMCC, for a lot less than one can spend on such things.

It is a bit of an oddity. It seems genuine, it has a Lucas part number and is made of parts of approriate 'quality'. It is marked '1980', and I guess it was a replacement part for vehicles still using red spot ammeters. It is marked 'Lucas' on the dial, but it does not have a window in the back, like the earlier versions that would have graced Amelia's curves when she was new, and it has no facilities for an ignition lamp internally so it could not have functioned as the red spot ammeters were intended to do.

The plan is to replicate the parts used for the ignition lamp and to cut the window through the ammeter, so that we end up with a suitable white faced ammeter with the functionality that we need.

So, starting the work. Here is the back plane of the meter, with it's insulator. I've marked out the holes I need, and I've drilled a pilot hole in each. Then I have taken my piercing saw with it's V-table and carefully cut the shape we need for the ignition lamp aperture. I've cleaned the hole up with needle files.

Here is the back of the ammeter, the back plane and the insulator, all assembled and showing the aperture lined up. Not quite right yet.

Here's are the prototype parts for the ignition lamp. Following the style of the original ammeters, I have used a plastic card to replicate the tufnol insulator that is used to mount the lamp holder, just to get the shape, and the position of the lamp correct in relation to the aperture on the back of the meter.

The lamp holder is mounted on a small piece of 0.5 mm aluminium sheet, pop riveted to the insulator. There is a plastic insulator between the centre terminal of the bulb holder and the mounting bracket.

So for now, the lamp is in the correct place. We will reassemble and see if it looks OK from the front, when it is illuminated, then we will make some nicer parts.

Here it is, put back together with the ignition lamp off...

And here it is with the ignition lamp on! Isn't it exciting!

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.