Model A - magneto chain case

 The magneto has been sitting on its platform behind the engine for some while, ever since it came back from Tony Cooper. I'd left it off because I wanted some time to look at the seal between it and the back of the gear case, and I'd also posted some questions on the AOMCC Facebook page to try and learn about the two breathers that route out of the gear case and onto the chains. This post is about those two issues.

Let's start with some pictures. This is a page from the 1930 heavyweight parts book:

Club member Michael posted these three pictures on the FB page. This is a 28 bike which is not the same as 29 or 30 but gives you a flavour of what they would have used to implement these breathers.

Emerging from the crankcase, we have a breather emerging to oil the primary chain:

The equivalent pipe on '29 and '30 bikes appears from the back of the magneto chain case as shown here:

We will use the illustration in the parts book to invent something to head cross to the primary chain from here. It will have to have something to attach to though, to stop it wobbling about.

This is I think an S21/1 oil pipe union with its associated union nut and a broken nipple. The parts book identifies two of these unions and the other one fits into a hole right underneath the magneto chain run which is not visible in the picture above, but the hole is clear and the thread is good.

These next pictures shows the rear chain oiler on Michaels '28. Below, we see the pipe emerging from the timing gear case and disappearing in front of the gearbox - mine will be similar, but it comes from the bottom of the magneto chain case as I said.

What we are seeing in the picture below is the other end of the same tube emerging from a gap in front of the gearbox and running along the frame rail under the gearbox sprocket, flicking up and over onto the chain. This is shown in the 1930 parts book picture above as item A6/683, but just to confuse you the parts book picture is upside down.

This is the relevant page of the 1930 parts book. We can see here that there are two S21/1 unions called up so we can be confident that if we can replicate the one we've got, will be good for the other. The next puzzle is to work out what the A6/120 component does.

This last picture shows the three elements of the magneto to chaincase seal. Left to right we have the retaining washer, the Vellumoid washer, and the felt washer that pushes up against the chain case. The Vellumoid washer is basically a thick gasket that sits across the front of the Magneto - Vellumoid are actually still trading as gasket manufacturers. It's all in reasonable shape and I put it back in as I found it.

Magneto bearing puller

 With these old bikes every new job is a challenge. I suppose I could have sent the dynamo away to be refurbished like I do the magnetos but they're not that complicated so I do them myself. 

The E3 fitted to the Model A is a little bit different to the later E3Ls and E3HMs that I've worked on in that it uses magneto style bearings with separate races, cages and balls. Simple enough you might think - well yes, if it all goes to plan. 

What I discovered was that the reproduction armature that I bought for the E3 on the Model A, the first three-brush dynamo I have worked on, wasn't quite the same dimensionally as the old bent armature that came out and I found when I fitted the bearings for the first time that I had far more endfloat than I could cope with. To fix that you need to remove the bearing again, put a spacer in behind it to take up the end float, and fit the bearing back again - and you might end up doing this two or three times.

You need a special puller to remove the bearings and I found the details for one here:

https://www.kynoch-douglas-parts.com/html/articles/magneto%20bearing%20extractor.htm

The main tube part of the puller is made from a bit of old handlebar which I've turned internally to make the hemispherical form that will fit into the bearing race.

I turned up a plug to go in the end of that with an M8 female thread in the middle and welded it into the end of the tube. The six slots were cut with a hacksaw - you could make a much better job with a slitting saw but frankly I didn't want to work of setting it up.

There are a couple more details - the end of the threaded rod has a small disc welded to it to bear on the end of the armature shaft to reduce the likelihood of damage and the other end has a t-piece to allow you to turn it easily.

Here it is in action. Initially I used a regular worm drive jubilee clip to hold the six legs into the bearing, but they are just not strong enough and will pop out. The worm drive does not allow you to put sufficient force into the legs so I have used a much better quality hose clip - this trunnion type clip:

It works very well but you do need quite a lot of force to remove those bearings.

Model A - magneto

 As usual, I will be using the services of Mr Tony Cooper of Halesowen to rebuild the magneto for the Model A. I spoke to Mrs Cooper today and learnt that Tony would be able to rebuild the BTH KC1 for me. He's done the magnetos for both the FH and the W/NG, and they are excellent - the estimate for the Model A was a maximum of £250 and it would take 14 to 21 days.

This is how the magneto looked when it arrived. It's more or less the right period for the Model A but as you can see it is a slack wire advance magneto - Ariel specified a tight wire advance magneto. In theory, slack wire advance is a better option because if you lose the cable, the engine will still run optimally at speed - but it might be rather hard to start!

First job then is to remove the magneto. Fortunately this side of the engine is relatively clean and it's quite straightforward - it's just the same arrangement as the W/NG, built 12 years later.

Underneath I was surprised to find only two bolts holding the magneto down - the magneto is set up for four bolts, the W/NG uses three. 

With the magneto chain cover removed we can have a look inside for the first time, and it's all pretty familiar and pretty clean although the chain is very loose indeed:

All you have to do is remove the magneto retaining nut and then use the usual magneto pinion puller to release the taper:

You can then remove the two bolts holding the magneto to the platform and lift it out of the way. There appears to be a seal between the magneto and the chain case which looks like it is a felt seal sandwiched between two pieces of tin - it's black and oily at the moment so when it's cleaned up we can have a proper look.

Here are a couple of before pictures of the Magneto after it's had 15 minutes of fame in the parts washer:

Looks pretty good and turns easily. There's something wrong at the points end though - the bolt retaining the points to the armature makes contact with the brass end cover. One of these parts must be wrong, probably the end cover because in this arrangement the magneto will always be earthed and will not spark. 

Tony Cooper will sort all this out!

... 10 days later

It's back sparking merrily with a new armature and slip ring:

The end cover hasn't changed - but it turned out that there was a seal missing which stops the cover touching the point screw.

FH - points

 Just for the record, I have used the on-board points spanner (with built in 12 thou feeler guage) to determine that the point gap for both cylinders is identical.

This means the ignition timing should be similar on both cylinders.

The lock nut for the fixed point needs a 8 mm spanner, which I've added to the toolkit.

FH - shaking down 3

 Well, the mild spitting and reluctant starting returned with a vengeance today. After the tank pinhole repair, the washer around the speedo cable and some general bolt tightening I fueled up and took the bike for a short commute of about 4 miles.

It was certainly reluctant to start, and was also lumpy as hell but it got me there and restarted when it was time to come home.

The journey back got progressively worse, and by the time I turned into town I had only one cylinder.

That cut out as I turned into the yard.

The engine sounded flat and 'hard' on the way out, just like the W/NG when it's retarded. The blue exhaust pipe in the picture screams 'retarded' too - the bike went straight on the ramp when I got home.

With the plugs out, I engaged top gear to use the back wheel to turn the engine with the magneto end cover off - the points had virtually closed up. Setting that back to 0.012" had the engine bursting into life at the merest tickle of the kickstart!

I greased the point cam, but I must check the gap on both cylinders.

Shame about the blue exhaust. That won't polish out but at least the tank isn't leaking!

FH - getting there

 A few minutes in the workshop moves the project on a little bit: the speedo drive locating pin has arrived from the AOMCC gearbox man:

It fits in this hole:

A look at the carburetter reveals that the float chamber gasket is actually there, but that the drip shield is a little distorted and a bit loose, which probably caused the spitting back. The main issue, staring us in the face (and highlighting the perils of long-term projects) is that the carburetter needle is still in the box of bits!

The engine idles now.

By the way, I have changed the 210 main jet to a 260:

A couple more problems are revealed - the inlet rocker oil banjo is loose, and the magneto earth button doesn’t work. The inlet banjo is an easy spanner job; the cutout requires a bit more investigation.

FH - little bits

 A short visit to the workshop today got a few little bits done. I've removed the oil tank and fitted a bolt into the seat base above it, and I've tightened up all the seat bolts now so that is secure. Unfortunately in putting the oil tank back I cannot refit all the earth cables - I will have to remove the toolbox again to be able to get to the bolts. I do however have to order the voltage regulator to rebuild the RB108, so that will entail removing the toolbox.

Tidying up the bench I did manage to find the inspection cap for the gearbox so I have given that a bit of a polish on the wheel and refitted it.

I've terminated the HT cables and fitted the plugs so they are ready for first start - so that's oil, sparks, compression and a kickstart. All I have to do now is bolt the carburettor in place properly with some gasket sealant and I will be able to connect up a temporary fuel supply and give it a kick. 

This next bit is the rubber cable tie for the front brake. It doesn't fit properly because my mudguard with its repairs is thicker than was originally intended so what I've done is to increase the width of the groove in this rubber piece, so it should now fit.

The last bit today is just to record that the frame clip behind the oil tank has a new half inch long bolt specially made to complete the fitting of the oil tank.

FH - HT leads and plugs

 The FH is going to be fitted with a pair of Champion L82C plugs as an equivalent to the Lodge HN originally fitted. The rubber plug caps came with the refurbished magneto.

The HT leads, copper cored rubber, are the same length on both pickups. As I haven't consciously timed the magneto to a particular cylinder, they may be the wrong way round.

We will leave cutting them to length until we have it running.

FH - ignition timing

 Edging ever closer towards first start, I diverted myself from wiring activities to time the ignition.

Regular readers will know the rocker box isn't fitted yet, and I can tell you that it's much easier to set the engine in position for ignition timing without pressure from the valve springs trying to restrain you.

As I've fitted 7.25:1 pistons to this machine, I am timing it to Cyclone specification - 3/8" BTDC at maximum advance in place of the 11/32" for the home market models. Here it is on the ubiquitous Wagamama chopstick, of which I have hundreds:

The timing is set with the timing side piston at 3/8" BTDC on the compression stroke.

With the engine in the right position, I fitted my little clamp to hold the ATD at full advance. The ATD is screwed most of the way on, but is not yet on the magneto shaft taper:

With a green Rizla in the points, I can rotate the magneto until the paper just loosens in the points. It's useful to have a 4 BA spanner available to just hold the magneto shaft on that central bolt while you gingerly tighten up the ATD nut from the other side. With the petrol tank off, it's easy to reach the magneto from the timing side of the bike.

Next, fully tighten the ATD nut. You can then back the engine off and come back up to 3/8" BTDC; if the Rizla is just coming loose in the points (with the ATD still clamped to full advance), you are good to go.

FH - bottom end complete

A little bit later than expected I am back in the workshop. My generator decided to burn out it's alternator winding, and took the battery charger with it which meant buying a new generator, building a trolley for it (it doesn't fit where the old one was) and building a trolley for the welders - because their spot is now taken up by the generator...

Having got most of that out of the way, I can strip the cases again to fit the replacement connector rod nuts, BSA part number 37-1691. These are genuine new old stock from Vale-Onslow. Looking at the picture below, from left to right we have the modified Draganfly nut, an unmodified nut, and on the right the new lower profile nut:

This, by the way, is the mark left by the Draganfly nuts before I modified them:

Here are the Draganfly big end bolt washers. These are laser cut stainless and whilst some suggested they were rather small, they are much the same size as the bearing surface of the nut so I am leaving them in place.

Stupidly, I forgot to picture the new nuts in place on the big end caps. Mrs H phoned to see where I had got to (I'll just be 10 minutes dear!), and that's always a distraction. Suffice to say that they were torqued up to 22 lbf. ft in accordance with the BSA data sheet and I oiled up the various bearings before closing the cases. I made sure to remove all traces of Threebond and was very sparing with it when reassembling.

The case bolts are all stainless, from Acme as usual and they fit beautifully. I made this chart from the diagram in the Draganfly catalogue to show me where the different bolts go:

Lovely and easy putting them in; I used my frame spreader to make it a bit easier.

Now that the bottom end is in, we've got a number of workfaces to tackle:

• the barrel and pistons
• the primary case
• the timing gear

We can look at any of these really but before we do there are some components around the engine that will become less accessible as we progress. The first of these is the engine breather shown here in the form in which it arrived:

This isn't how Ariel designed it. It's supposed to bend around and appear behind the FERC, above the gearbox sprocket somewhere.

Another item is the magneto. It's fitted here temporarily with the long bottom nut, which is on the job list for zinc plating. With the primary case loosely bolted in place you can see that it's quite restricted in there:

Something that surprised me, and thanks to Daniel Rix on the FH Facebook page for this, is that you cannot get the brake bell crank on with the primary case in place. That's a pain, because I want to get on with the mechanical build and I hadn't planned on doing any plating just yet... and the bell crank needs plating.

The other thing I must remember is to fit the oil lines before I fit the primary cases! Access will be a trifle difficult if I forget, so let's not get ahead of ourselves and we will get on with sorting out some of the details.

FH Dry Build - Magneto Cutout Switch

There's lots of jobs to do on an old bike project - some dramatic, some messy, some tedious, some hardly noticeable. One of these is the magneto cutout, which is a small Lucas 76207 horn button mounted in a folded steel bracket to one of the handlebar clamp studs. It's here:

You'll recall I made some nuts last week - one of these was the locking nut for the cutout button:

The bracket will be a bit of 2 mm cold rolled sheet, but its a bit of an odd shape as it has to appear from under the top yoke, go forward under the handlebar and then pop out between the handlebar and the casquette. It took me three goes to get it right in cardboard:

I made the next prototype in 0.8 mm sheet which I could cut with snips and fold easily:

This looked OK but the switch wasn't quite in the right place:

It took me two more goes in this sheet before I felt confident that I wouldn't be wasting time if I went to the full thickness. Of course, at 2 mm thick it was going to need a bend allowance and it's straightforward to build that in during the marking out stage.

Here's a close up after drilling - you can see the double lines showing the position of the bends. I use a bend allowance equivalent to the thickness of the material - in this case adding 2.0 mm to each bend.

Here it is again, having been cut out with the hacksaw, filed and linished to the final shape:

I didn't take any pictures of the folding in the vice. I was careful to use the smooth jaws, have the bend line exactly aligned with the top of the jaws and to observe the bend forming as I pushed it over, such that the bend was formed between the two bend lines.

That's it. I've added it to the list of small bits to be zinc plated later.