FH Fuel Tank

The FH trial build continues with the tank fitting and inspection. At the outset the tank looks quite good - a bit scaly here and there but little damage as found:

One of the main reasons for the trial fit is that this is a late tank as befits the bike and as such it has a single point fixing, presumably derived from BSA who owned Ariel at the time. The single mounting bolt fits in a steel 'bucket' sitting in a hole in the middle of the tank.

The hole has had a braze repair which prevents the rubber being removed at anything other than a very jaunty angle, which makes it impossible - or at least very tricky - to get the bolt in. I've ground the braze back as far as I dare with a drum sander in the Dremel.

Removing the knee rubbers is next. The drive side is fine, but the tank has a shallow dent on the timing side. I'm going to get this professionally painted and I think I will ask the repairer to sort this out:

This is the chrome trim - it needs some work to make it fit:

These are the components of the centre mount, including the bucket and the tee bolt on the left. On the right is the nut and the centre rubber, which fits in the bucket, with its sleeve. The other rubber is one of the four which fit in the tank mounting holes on the frame - Ariel didn't change the tank supports on the frame from those that had been used since the 1920s.

Here's the centre mount in place:

The tank badges are there - in fact I have four to choose from. The chromes trims they sit on are pretty good, but I will have to find or make some shorter 3BA raised countersunk screws.

All in all, not too bad. There's a weld repair needed for the bar that the chrome trim fits to at the front of the tank, but nothing disastrous.

Model A - Front Mudguard

Since the FH is going to need some floor space pretty soon, I will need to move the Model A. I may even move the A onto the bench - we will see. I have had a front mudguard standing in its place for a while, which falls off every time i move the bike, so I really need to get that fixed.

I've had some black mild steel flat bar knocking about which I bought to make mudguard brackets like this and a dose of bending around various bits of scrap (a 6" length of scaffold pole is very useful in the workshop) had it more or less in shape.

The target shape was defined by various AOMCC members, notably Stan, providing pictures of original brackets.

I fitted the front stay first and let that dictate the mudguard's relationship to the wheel rim. I used an electronic level to establish the correct position of the stay, by measuring the angle from pictures of other bikes

The rolled edge of the guard needs to be flattened where the stay fits, in order to accommodate the width of this original stay:

Once I was convinced the guard was in the right place, I drilled the mounting holes to the forks:

Some time on the linisher had the ends rounded off and looking tidy:

In amongst the pile of bits that came with the Model A were both of the original number plate mounts and the number plate.

I placed these using a couple of reference pictures that I got from members of the AOMCC.

FH Fully Enclosed Rear Chaincase

Ariel's fully enclosed chain case was an optional extra on Huntmasters, and I didn't have one - but this appeared on eBay. It's pretty rusty but it is solid, if a little bent. I spent a lot of time getting it to fit together like this:

The main problem was that the bottom half had been squashed at some point - it's on the right in the picture below

This illustrates the problem. The bottom half mates correctly with the top half to the left of the axle, but it is way out on the right - the area below the axle is much less dished than it should be. I put that dish back with some light beating and formers.

The front area is fine:

It moves over the front section nicely:

W/NG clutch repairs

July has been a month of tinkering with little bike jobs. I use the W/NG a lot, because it's an easy bike to ride around the little lanes and to thread through busy holiday traffic - unlike the Square Four, which is much heavier, less nippy but is also more suited to the open road - faster, more comfortable and with a much lighter clutch. 

Talking of clutches, the W/NG's clutch was starting to trouble me a bit - it felt notchy, gear changing was getting more difficult to perform quietly and it was obviously starting to drag. I knew the plates, basket and centre were in good condition because I had pulled them apart when I rebuilt the engine late in 2020, but the operating mechanism had not been touched.

Here's the first observation. See the pushrod? It's not supposed to be dished like that, so that was obviously knackered. The little bronze bush wasn't in too bad condition, but it was very loose in the gearbox cover:

Next - the arm is not supposed to pivot on an M5 bolt. This gave rise to a lot of lost lever movement as the larger of the two holes in the arm is threaded 1/4" CEI:

The pushrod was dished at the other end as well, as someone had fitted a ball in the pressure plate:

I looked around for a new pivot pin for a while. These came from AOMCC Gearbox spares:

The bush is held in place with Loctite 603 Retaining Compound:

All back together and feeling a lot better. I just need a road test now, though I think I may need a new set of clutch springs. It's been difficult to get the pressure plate level without one of the springs ridiculously loose....

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.

FH fuel tap

The Owner's Manual for the FH describes, in several paragraphs, how to operate the fuel tap and makes it very clear that the tap specified was not the usual two-plunger tap used by Ariel since before the war. In fact the manual tells you to pull the plunger to turn on the main supply, and then to twist and pull it again to get reserve. It took me a few eBay mistakes before I found the right one, courtesy of John Mitchell of the AOMCC. 

The tap John sold me was in great shape, but it was missing the filter and the main supply pipe which draws the main supply from a point above the water in the bottom of the ethanol-laden fuel. Since I have other taps with this pipe, and I have made several filters, it was no problem to make the missing parts.

I started with a bit of 3/16" copper tube which I annealed with the wonderful Rothenburg Superfire torch. I set the tube up in my cable nipple swage:

Using a centre punch & a pin punch, I belled out the tube until it was a tight fit in the register machined in the tap.

Next step was to make a little cylinder on the lathe to position the pipe within the filter. This is machined internally to fit the tube and externally to the same diameter as the filter, and soldered in place at the top end of the tube:

So there we have it, the components of the tap:

To assemble the tap, I pushed the swaged end of the tube into the register machined in the tap body - I didn't attempt to solder it in. I then pushed the tube into the filter, and applied some flux to the tap body where the filter sits and around the cylinder I made earlier, through the filter gauze.

When soldering the filter onto the tap body, you need a fair bit of heat - I use my kitchen blowtorch for those sort of jobs.

You'll notice the tap has a fibre washer - I usually use Dowty washers in this application, but there was no way the plunger was going to 'fall easily to hand' with a Dowty washer on the tap - so a thinner fibre washer it had to be.

SQ4 gets a new tank

A long while ago, I confessed that I had realised the tank that my SQ4 kit arrived with, and which I had painted at vast expense was not a Square Four tank at all, but one which had once belonged to a KH Hunter twin. It did look good though:

It looked even better on the bike:

I started to look for another tank and after a short interlude with a very rusty tank from Denmark I found one in original paint at Yeoman's Motorcycles. When they are on the bench together, you can see how different they are:

So now, with a new tap (actually a refurbished original) and a balance pipe, here is Amelia in her latest incarnation:

Model A - new bits from club spares

 I had a nice little present from AOMCC Black Ariel Spares this morning:

Here we see a pair of footrests, a brake pedal spring, the gearbox adjuster and a valve cap spanner.

Model A - Rear Brake Rod

 The rear brake rod is a much simpler affair than the front - it has a clevis at the rear end and this just needs a new pin, which is easy to make on the mini-lathe using a tailstock V-block:

The brake rod is just a bit of 1/4 round bar, threaded 1/4 CEI for the adjuster. The clevis is there, though very worn and we can find a spring from stock. The adjusting knob is missing, so we will turn that from a bit of 303 round bar, 1 OD:

It's reduced to 1/2" at the rear end, and the front appears to be domed but other than that is is similar to the front one. Same straight knurl:

Dome is made after parting off, with a combination of turning and a bit of filing:

We can mill a shallow groove in the rear to accommodate the clevis using an end mill.

Job done, though I think that trunnion will need replacing.

Model A - front brake rod

 The Model A came with its original front brake rod, but none of the fittings. It's an odd design - the rod is 3/16" (0.1875") but, to prevent rotation in the brake arm, it's flattened at the end. This makes it larger - it's actually threaded 1 BA, on a major diameter of 0.209".

Of course, cleaning up the thread is a bit of a challenge with the flat since many dies will not bite having three sets of flutes, or very narrow flutes, as the thin rod disappears into the gaps. 

Here's my stock 1BA die:

See the narrow flutes? This next picture is another I bought:

The flutes are much wider on this one, and I managed to recover the thread and get my newly-turned adjuster knob to fit. It's made from 303 stainless steel on the lathe, milled for detent on a 1 BA mandrel in the toolpost:

The outside is cut with a deep straight knurl, slightly chamfered:

The next lathe job is the spring housing, copied from the one on the W/NG. It's a bit of 1/2" 303 round bar with a 1/4" CEI thread in one end, bored 9.5 mm for clearance on the 3/8" brake rod end: