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.

FH - toolbox, charging and other progress

 The toolbox is back on:

In other news, the primary case now has oil and the FERC is no longer dripping oil all over the bench. The oil tank now has a felt wick for the chain case feed:

It's made from a strip of felt, 10 mm x 10 mm x 25 mm:

I made this short video to record the fact that the battery is now charging after we re-polarized the dynamo and updated the RB108:

Doesn't the engine sound great! I got it started a couple of times using Easy-Start, but it only ran for a second or two. Playing around with the fuel supply, I eventually tickled it for a long time - until I had a flood under the carburettor. It started and ran perfectly, but needs choke - perhaps I am starting to learn the technique?

To report on a couple more things: the clutch cover screws are a bit short of thread - there is a 1/16" unthreaded section under the head - cutting the thread on that bit will allow them to go fully home. I've put shake proof washers on them for the moment.

I've failed to improve the front brake - any more turns on the adjuster just lock it solid. It will have to come apart.

The oil banjos on the rocker box are in good shape - they have a lot of contact area though, so they have to be very tight to seal. I've smeared a bit of Wellseal on them which seems to have done the trick.

Number plate next, then the instrument panel and lastly the fuel tank.

FH - wiring the dashboard

 This will be the first time that I've wired up an Ariel with the separate instrument panel fitted to the swinging arm frame bikes with the headlamp nacelle. Looking at the wiring diagram it makes sense to wire up the panel separately from the rest of the bike, to be fitted later.

As you've seen, and in line with the wiring diagram, I have fitted a 5-way bullet connector between the main harness and the front end. Some of the cables from the instrument panel will go into this multiple connector, and others will stay on the panel whilst further connections will go into the headlamp. 

I made a start on the panel by fitting the ammeter and the light switch. I had the speedometer fitted as well, but found that the speedo lamp fitting was loose in the speedo body and the bulb holder could not be removed so I've sent this off for this to be repaired and the speedo overhauled.

Here's the initial layout. I've put all the wires in and crimped the ring terminals; the next step is to try this on the bike and see where the cable is going to route and how I can tie these cables together in sleeving.

This is the result. You can see I've terminated all the wires now, and added some sleeving and routed some of the wires around the top of the speedometer. I can't do much more until the speedo is back from Russell.

I need to clip the switch in and add the rubber ring around the switch and the ammeter, but it does work and I have both a rear lamp and a stop lamp. For some reason the horn doesn't work? 

It's alive!

Next stop on the wiring list is to add the combined horn button and dip switch. This is the original one and I have just removed the old wiring and clean the switch up with degreaser. More of that later.

FH - Ammeter rebuild

Way back in the dim & distant past, when I was still working, I rebuilt an ammeter for a friend and blogged it as ‘Tim’s Ammeter’. This is another one, a similar 0-8-0 amp CZU27 from the Huntmaster kit. It’s not in bad shape.

It’s a bit grubby and scratched as you might expect, so I will pull it apart for a clean. There isn’t much glue on this one and it comes apart easily.

All in bits with nothing broken:

Here’s a curiosity - it’s dated January 1960. It must have been replaced at some time, though it’s correct for 1958.

It cleans up nicely:

This is interesting. The power supply is set up for constant current:

These aren’t hugely accurate! This is actually at full scale deflection, but as you can see it’s only passing 7 amps.

FH - Ammeter identification

 Despite concerns to the contrary, the 1957 Lucas Parts Catalogue confirms that the ammeter should be a Lucas model CZU27, PN 36084:

It looks like this:

And here's the one from the FH:

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!

Charlie's Shed - W/NG Dynamo Repairs

 Some while after fitting the new headlamp and instrument panel, I became aware that the ammeter rarely showed a charge. At the time, I assumed it wasn't centring properly and resolved to pull it out and adjust the needle. However, obsession being what I'm known for, I kept an eye on it and eventually realised the needle intermittently showed a charge. There had to be something wrong.

Following the usual checks (voltmeter on the battery, linked D & F cables with voltmeter to earth, connectivity checks) I realised the dynamo was struggling to go past six-point-something-small volts.

I went inside, and here is what I found:

That's it - goop and copper dust. I sprayed it with brake cleaner and put it back on the bike, with the brushes now sliding in their holders. A few trips showed a steady improvement, but it still wasn't right. Waiting until I had a few hours I could dedicate to it (it's in daily use, more or less), I took it off again and stripped it down to find the shims that one of the previous owners had fitted (and I had re-fitted) to accommodate the non-standard bearing had moved and cut into the commutator, shorting out the segments intermittently.

I resolved, after much deliberation, to bring the bearing arrangement back to standard. As part of the process, I cleaned up the commutator on the lathe:

The bearing came off after a few minutes with a grinding wheel in the Dremel. It wouldn't budge for a puller, but the Dremel cut through the outer race easily so that I could split it and pry off the ball cage without damaging the segments. I ground the inner race tangentially until I was almost through to the shaft, when it cracked and came free. The shaft was in good condition underneath, measuring a hair under 7 mm - odd, because the Lucas parts book suggests the internal diameter of the bush at this end is 8 mm. This must have been enlarged post war - this dynamo is marked 1943.

In a footnote to this, I realised the E3L fitted to my FH has ball bearings at both ends. I wonder if this E3HM has an E3L end bracket?

These are the culprits - two pieces of thin steel:

I made a drift to knock out the old bush:

I turned the new bush out of a bit of SAE 660 phosphor bronze I had. This is a bearing bronze that is considered the standard bearing material for light duty applications. It is easily machined and the bronze alloy is hard, strong and resistant to wear. Apparently it also conforms well to journal irregularities and is less dependent on lubrication than other alloys.

I drilled it 6.5 mm and reamed it 7 mm:

The old bush measured 11.2 mm outside diameter and pushed out easily. I made mine 11.3 mm and whilst it went in with no trouble, it was considerably tighter than the old one. I reamed it again when I had it fitted and deburred the ends.

The clean armature journal fitted beautifully and I reassembled the dynamo, pausing to look at the drive end which seemed to have a lot of end float, though in fact it was around 0.5 mm.

I attempted to motor the dynamo on the bench, but unfortunately the only loose 6V battery I had was completely flat. I refitted the dynamo to the bike, and started the engine to find the ammeter kick over to the 'charge' side with a few revs. Job done, except for the felt washer around the bush which I don't have at the moment.

Another small job I wanted to do was bush the end cover retaining screw hole (3/16" BSW) which has stripped. Unfortunately there is not enough room to fit my preferred M8 bush, which is plenty big enough to tap 3/16" or even 1/4" BSW if you have to, so I re-tapped the hole M5 which is a little bigger than 3/16". I'll have to think about that some more - perhaps go for an M6 brass bush which I can drill and tap 3/16" BSW.

Tim's Ammeter

This is Tim's CZU27 Lucas ammeter, from his Matchless single - the very common 8-0-8A instrument that's found on many of our bikes, and it doesn't work. The bike doesn't charge, and the ammeter is off centre. Tim has a repro replacement but this is the original one from his bike, and so it's important that it's repaired and goes back to the hole it's been living in for the last 60 years.

Here's Tim's bike - a G3LS that looks about 1957 to me, still has the pressed steel chain guard but has the new Girling shocks that replaced the jampots in that year:

Checking the ammeter with the multimeter shows that it's showing open circuit, so we are going to have to take it apart.

These meters are made with an acrylic plastic housing that forms the lens and the body, and the separate back is glued in. The glue goes quite hard and brittle and can be scraped out - but there is often some case damage around the edges:

I use a tool ground from a small screwdriver to scrape the glue away:

The dial usually gets caught up in the glue frenzy. It has four feet which clip to the base of the ammeter and these get glued down as well. Here are all the bits separated; notice how the dial has faded. There is a shadow of the needle on it:

Here's the whole thing dismantled (dial is not in this shot), and there is a couple of washers missing:

Closing in on the problem, we can see that the coil connection has broken - a fatigue failure, probably:

Here's the coil removed from the back plane:

The other eyelet:

Easily repaired, we can open the swage on the loose eyelet, clean the end of the coil and re-swage. We'll solder this joint and then re-lacquer the coil.

Soldered up:

On to the back. It's straightforward to repair the break with a suitable medium-viscosity cyanoacrylate, but using a technique I picked up while repairing guitars we can drop-fill the missing bits as well.

While I repaired the base, I noticed the part number stamped into the back plate:

So this ammeter was made in August 1966. Fifty-two years service is not too shabby!

For reassembly, start with the coil, the large Tufnol plate and the two domed screws. assemble them with the small Tufnol washers like so. Make sure the magnet is in its recess in the back plate:

The two large Tufnol washers isolate the terminal with their brass nuts from the backplate:

Remove this lot again and assemble the backplate to the repaired base:

Add the backplate, terminals and coil:

Assemble the Tufnol washers through the base and tighten the brass nuts:

Use a watch oiler to lightly lubricate the needle pivots

Assemble the dial onto the backplate assembly and add the needle. Screw down the needle pivot until it just moves freely, with no shake

Test the ammeter in both directions. This set up is just a 9V battery driving an H3 halogen bulb - which draws quite a lot of current and serves to show the ammeter deflecting:

Reverse the polarity to drive the ammeter in the opposite direction:

Make sure the dial has no damage to the legs. if the dial catches on the case, it will bend the needle when you remove the case.

Seal the dial legs to the case with a suitable weatherproof glue, preferably one you can easily remove:

Glue the top of the case in place and clean off the excess

Seal the needle pivot thread with nail varnish and you are done.

Brightspark have some useful information on these ammeters here:

http://www.brightsparkmagnetos.com/...Ammeters.pdf

As do the Vincent Owners Club:

https://www.voc.uk.com/net/docs/tl/lucasammeter.pdf

And I've rebuilt my Red Spot ammeter:

http://ariel-square-four.blogspot.com/search/label/Red%20Spot%20Ammeter