Sunday, 30 July 2017

Making a number plate

It's getting around to the time the W/NG magneto should be back from refurbishment, so we might be able to ride it soon. Time to make a number plate.

First, you need to find the right font. For our bikes, we need to print the number in Charles Wright Bold, 64 mm high letters. I used this site

You can type in your number, and the page will display it in the chosen font:

You want to size it to 96 points and capture it using alt-print screen; you can then paste the picture this creates into MSWord. You'll end up with a picture which you can stretch larger - resize so the letters are 64 mm high

Print it out in light grey, so you don't waste lakes of ink. Stick the print on coated paper; it's going to get wet, and you don't want your stencil falling to pieces. I used a discarded magazine cover.

Cut out the letters with a scalpel.

I made a bridge out of the letters to hold the middle of the '8', using double sided tape:

Apply the stencil to the number plate & retain with magnets. The dark shapes are pieces of broken magnet:

When I do this again, I think I will buy some of that magnetized sheet; then I can cut shapes that hold the stencil in place, or maybe I will cut the stencil from magnetic sheet...

Spray the colour of your choice. I used Ford Ivory White, left over from the Bantam tank panels.

Now, before the paint dries fully, remove the stencil and clean up overspray when the paint is hard. I used wire wool and Farecla G3 cutting compound:

It's almost there, but could do with a bit more cleaning up. What I like about this is that the ivory colour and the slightly uneven lettering fits well with the patina of the bike as a whole.

Wednesday, 19 July 2017

Lucas SSU700 Side Lamp Holder

A few pictures of the SSU700 Side Lamp Holder I made early on in the SQ4 rebuild.

I've fixed a LED sidelamp in it, from Paul Goff.

The bulb holder slides under two grooves cast into the underslung sidelamp housing, and is stopped by the two ears formed on the sidelamp holder:

In case anyone is interested, the Lucas part number is 516597...
This is a real one, from AOMCC member Lee Mallabone's KH:

Wednesday, 12 July 2017

Girder Fork Damper 'Wing Nut'

Since I've had the W/NG, the 'wing nut' used to adjust the fork dampers has been missing a wing. Unable to find a new one, and not afraid of trying anything new (especially when challenged by other AOMCC members) I decided to repair the old one.

One thing i don't much like about old bike restoration is the notion that you can buy a new part rather than repair the old - replacing bits is not 'restoration' to me. This is the old nut, removed and cleaned up:

I selected a bit of scrap, the flattened end of a stop cock key:

I chopped a useful bit off and filed it up to shape. Near the end of shaping, I heated the new part and flattened it where I was to weld:

Old part and replacement end:

Set up in the vice for welding:

As usual, I used the TIG to weld it up, set to about 45 Amps with the tungsten ground with a shallow angle to give better penetration:

Next, some more filing. Not looking too bad here, but needs more work; the new end looks distinctly heavier than the original:

And back in place, ready to get some patina:

Tuesday, 11 July 2017

Getting a grip on Repro Parts

Today, the Bantam got some NOS genuine Amal grips. Much better than the reproduction ones she had been wearing:

Monday, 10 July 2017

Occhio Lungo

Occhio Lungo - the 'far seeing eye' is one of my favourite sites. There is some very impressive 'how to' stuff here:

Sunday, 9 July 2017

Holiday Snaps

I've added a new page to the blog, telling the tale of an AJS Model 30 I had in my youth. MAP 984 now adorns a Mercedes according to the DVLA, which is a shame - I wonder what became of the bike...

Oil Purifier

You might recall that I was working on the oil pump, sump and other areas before my attention was diverted by a damaged timing case and a magneto that was playing up. Since those are on the way now, its time to attend to the lubrication system again.

Ariel provided a sludge trap, shown in the picture as a plug in the offside flywheel, which traps particles circulating in the oil. You pull it out periodically through the sump plate and clean it.

Here it is, alongside the pickup pipe. The purifier appears when the engine is at TDC, despite what is shown in the drawing:

They can be a bit of a job to get out if the hexagon is mangled. I was lucky - this one is perfect:

You need a good fitting socket to get the oil purifier out safely. Here it is, full of sludge. If it's anything like the sludge traps on the SQ4, it will be very hard:

Here it is, cleaned out:

Although the purifier itself is clean, we can see that it's been so long since it was cleaned that the drilling in the flywheel which leads to the purifier is also blocked with goop. I cleaned this out with a 1/2" twist drill.

Part way there:

Once I had got as much as I could out, I injected oil into the end of the crankshaft to clean it further. I did this first with the purifier out, and then, having put the purifier back in, I tested communication from the end of the crankshaft to the big end.

Oil dribbling out of the open sump plate proves that the big end oilway is open.

Saturday, 8 July 2017

Rotating Footrest

Fixing the magneto and the timing case means that I have an opportunity, with a little more dismantling, to fix another minor problem that the W/NG appeared with after its leisurely Italian sojourn.

Fixing the footrests last year I found that the peg on the engine plate, that prevents the footrest from turning was missing on the offside. I fixed this temporarily with some 4 mm rod I wound around the footrest and poked in the hole left by the missing peg.

Removing the magneto platform is straightforward, and demonstrates why the 1/2" headless bolts have to go in from this side. One of them needed the thread chasing out and some of the washers are missing.

An Ariel single, with an engine plate out:

Here's the plate as I removed it, covered in grime. Notice the hole:

I'm loving the parts washer:

Here's the inside of the plate. I've welded in a short length of 1/4" steel rod, which I'll cut to length later.

Here's the repair from the other side, after cutting to length and priming:

Painted black:

And back in place:

Sunday, 2 July 2017


The few test rides I've had on the W/NG have been successful in that I know it steers straight, stops, selects all gears, and doesn't have any horrendous sound coming from the engine. They've not been so successful in that they have all been shortened due to the engine dying after around 10 minutes!

Investigating these kind of issues always swings to and fro between the carburetter and the magneto. I used the guide from the Brightspark website to investigate the magneto. This is the sequence they suggest - full details are on their website:
  1. Bearings and Bearing Insulators
  2. Pick-up, HT Lead and Plug-cap
  3. Slip-ring
  4. Contact-breaker Assembly
  5. Cam
  6. Internal HT Continuity
  7. Main-body Earth Brushes and Bearing Insulators
  8. Contact-breaker Re-installation and Points Setting
  9. Low-tension Continuity
  10. Earth Brush Continuity
  11. Complete High-tension Continuity
While the magneto was sparking, and usually starting the bike successfully, it was clear that all was not well as it would show no spark occasionally. Even spinning the machine with a power drill would only produce a 3 mm spark, though it was consistent and continuous. It needed further investigation.

The first job is to remove the magdyno, which is easy with the timing case off - just three bolts.

First I looked at the bearings. Holding the contact breaker and the drive shaft, you can attempt to move each end axially and radially to detect play in the bearings - there was nothing.

I checked the resistance of the HT pickup, lead and plug cap - very low indeed. These removed, we can look at the slip rings:

Not an easy thing to photograph, but the slip ring is a little greasy. This particular picture shows the slip ring near the HT coil spike, which is a small piece of wire connecting the HT circuit to the slip ring:

Clean it up with acetone on a swab. These Wagamama chopsticks are so useful:

Rotate the armature until the swab comes out clean:

This is the HT circuit resistance, from the slip ring to the armature earth - 9.69 kOhms is way too much; it indicates that the HT coil is probably sound but that the connection to the slip ring probably isn't.

HT circuit resistance requires the armature to come out and probably the slip ring to be removed. Since this involves pulling off the bearings, and that needs a special puller, this problem means the magneto will need specialist attention.

The next picture shows the resistance of the armature earth to the magneto body - essentially testing the path through the earth brush. 2.6 Ohms is OK.

So, having identified a fault that I am not prepared to fix, its off to a specialist,  packed in a purpose made plywood box.

It should be back in a few weeks.




And here it is. It's had a new armature, since the old one was undersize and affecting low speed performance; new bearings & insulators, new points, condenser, slip ring, pickup and its been blasted clean:

I can get it to spark just turning the armature in my hand, and the bike starts instantly.

Tony Cooper, 110 Olive Lane, Halesowen, West Midlands, B62 8LT. Tel: 0121 559 2405, was responsible for this fine piece of work. Tony has rebuilt more than 5500 magnetos so far...