FH - A few odds and ends

 With an hour or so to spare, I went to the workshop to finish putting the tank on the Huntmaster. Bolting it down was no problem but I noticed a drip from the tap. The plunger was very loose and I imagined the cork might have dried out since it had been empty for quite a long time. I was wrong about that - the cork was just knackered. 

Fortunately I have quite a lot of spare plungers knocking about and I found one with a good cork that I could plug the tap with whilst I repaired the original. It's the usual drill here with these post-war taps - you knock out the brass centre using a punch, replace the cork with a new one, and put the centre back in. In taps where you have to twist the plunger, the centre is actually formed as a square at the outer end and there wasn't sufficient material left here to re-peen the brass end into the chrome handle. I filed the end back a little bit to give me more length and used to centre punch to peen it into place:

The next job had been coming for a while. The chrome strip which hides the welds on the top of the tank broke at the hook holding it onto the end of the tank. I toyed with the idea of buying a new one for a while and then realised as it was brass I could probably make new hook, soldering it in place of the old one. 

I made a new one and used some solder paste to tin both the strip and the new hook adding some extra solder to it once tinned.

I held it in place with some clamps whilst I sweated the joint together.

That worked really well, and is more secure than it has ever been.

FH - fuel line

 Here it is, burbling away at the top of the road looking marvellous:

The brakes are a little better but still don't inspire much confidence. I have adjusted them again but it's likely that we will re-line them when the wheels come off again. I've also corrected a slight misalignment in the rear wheel.

Keen eyes will note it's still wearing the temporary fuel tank in this picture - it's time to make a fuel line. These are the bits we need - some 1/4" fuel pipe, two ferrules, fittings for each end of the line and the little swage we made years ago from two bits of 1/2" square bar:

Fit the ferrule over the end of the fuel line and push the fitting in, being careful to orient it to suit the natural bend in the pipe:

Put the two halves of the swaging tool around the ferrule and nip it up in the vice. When you are happy that it's all in the right place, give it a little squeeze but don't fully close the swage; then turn the ferrule through 90° and squeeze it again. Doing it all in one go will probably split the ferrule on two sides.

There we go - nice neat job:

And back on the bike. The pipe could probably have done with being 1/4" shorter but it is tidy enough for now.

FH - petrol tank

 The tank trims and rubbers were not a job I had been looking forward to. The trims were a bit mangled - they are thin aluminium, available new but very expensive and of course as I have said multiple times, I won't be a 'cheque book' restorer - and I knew they would have to be 'manipulated' to get them back on.

They fit around and underneath the welded plates that retain the rubbers, bending down into a depression on the tank (the bit I had cut out and rewelded) with a beaded edge laying flat (!) on the tank, around the knee rubber. Like this:

It doesn't look too bad does it! I removed a lot of dents with some purpose ground punches and a simple hardwood dolly, with grooves to suit the beaded edge:

The next bit is a job I don't enjoy very much - I am always afraid of tearing the rubber or scratching the tank. A smear of silicone grease helps, as does remembering (eventually) that you start fitting these at the rear, narrow end and move forwards.

If you start at the back, the bottom edge will go in easily and you can work along the top edge; you can then slip the front over, as there is quite a lot of length to stretch and it will move, leaving you with a bit in the middle of the top edge which is a bit of an effort. Very rewarding when it pops in though, and made much easier by the fact that the tank, on the bike lift, is at shoulder level.

A couple of other points - I polished the trim up on the wheel before it went on, and secondly it's much easier to fit the rubbers when the tank is bolted in place on the bike.

Talking of which, as a 1958 bike this tank has the single centre fixing beloved of BSA. I wonder whose idea it was? A Val Page idea or a BSA idea? The easiest way to fit this is to assemble the bolt, washer, nut and the rubber with it's tube and insert it into the hole in the tank. With the seat pushed to the rear, you can lift the tank and wiggle the head of the bolt into it's slot on the frame - then you lower the tank.

You'll be able to feel that the bolt head is still engaged as you do up the nut.

We'll fit the chrome strip in the next episode!

Coming around to filling the tank, experience has shown that a petrol tap cork that has not had a tank of fuel sitting above it will dry out, shrink, and leak profusely. I've removed this one and it is spending the night soaking in fuel.

The tap itself is fitted with a Dowty washer which will make a far better job of sealing than the fibre washer originally specified. I've sanded the paint off the sealing face in order that the seal works properly, and a miracle has occurred:

The tap is positioned perfectly and it is fully tightened!

W/NG - Cleaning the fuel tap

 One embarrassing thing that happened last year was a shortage of fuel - or rather not. I ran out of fuel out in the wilds of Norfolk having given son Thomas a lecture about coming out without checking the tank, discovering a little while later that not only had I run out of fuel but that the reserve tap wasn't working.

Emptying the tank, I pulled the tap off to check and found the filter torn and the reserve port full of paint chips:

A few minutes poking around soon had that clear, and I fitted a new filter:

I realised later that this one is of a coarser mesh than I would have liked - I'll have to replace it again...

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:

Charlie's Shed - Petrol Tap Filters

Updated from December 2017

Many of the fuel tanks we have on our bikes are not in the best of condition and may be flaking rust or paint from inside, or worse, your tank liner may be in the process of falling to pieces. It's essential to have a good fuel filter.

Here are a few I made earlier:

Most of the fuel taps I have acquired have had either missing or holed filters, and, having had very limited success with the inline filters on the market (poor fuel resistance in plastics leading to cracking & cloudiness, or a ridiculous flow coefficient leading to fuel starvation) I have set about replacing the missing in-tank filters. This is typical of the damage you will find, if not a lot worse:

These are pretty simple to make if you are reasonably adept with a soldering iron. Start by removing the old one. I use a kitchen-type blow torch for this, which is plenty hot enough for sweating soft solder:

Hold the intake tube with a pair of pliers and twist it gently when the body is warm. It should come free quite easily

Look for the finest mesh you can find. The originals are a very fine copper mesh which is easy to obtain (though the mesh in the pictures is actually brass). Cut a suitable rectangle with scissors.

Start to form the cylindrical shape around a pencil.

You'll see that the final size for the filter on this double-plunger Ariel tap is very close to the diameter of an AAA battery:

I use a chamfered edge on an old credit card to form a tiny lap joint on both edges of the gauze, like I did with the oil strainer on the SQ4:

I then roll them around, mating up the lap joint and folding it down tight on the AAA former.

You can make a simpler lap joint like this:

Solder the joint with a small iron:

Flare the end to fit into the recess on top of the tap:

Have a good look at the recess on top of the tap. Make sure you clean out the joint of all goop, old fuel, rust and old solder. We are going to tin this area and sweat the new filter in.

Put the main feed pipe back in and trial fit the filter:

Now, push your AAA battery former up to the other end of the filter and form the closure:

Lay some solder onto the flare:

Lay a little more solder onto the end closure:

Flux the top of the tap and using a small blowtorch (the type you might use in the kitchen) apply some solder all around the joint, without the filter in place. Let it cool and clean it up and have a good look to see that it has run all the way around, then add the filter. Reheat the tap just sufficiently to melt the solder , and the heat should transfer to the solder ring around the filter flare allowing the two to fuse.

You might notice that this tap is fitted with a 3/8" BSP Dowty seal - makes a better job of sealing that joint than a fibre washer.

If you still have problems with your tap, check my post on replacing plungers here.

Thanks for reading, and I hope you found it useful.

Charlie's Shed - Fuel Tap Plungers

If you find yourself short of plungers, or the shaft of your adjustable plunger is damaged, they are quite easily made if you have access to a lathe.

The brass centre of the adjustable plungers, which is often short from having the slotted end broken, can be made from a bit of 3/8" round bar. Chuck this in the lathe and turn a suitable length to 5/32" - the best way to do this is to turn an 1/8" or so to exactly the right diameter, then use this short length as a guide to turn the rest in one pass. With a sharp tool this shouldn't be too much of a problem and it avoids the tiny bar bending away from the tool, which will result in the outside diameter being over size.

Chamfer the end and cut the thread - it's 5/32" BSW. Make sure you use a tailstock die holder or back the die holder up with the tailstock to keep it square - you don't want that thread wandering off.

Give it a polish and part it off:

Assemble it into the plunger and you are done:

The shaft I have made here is a bit over-length compared to the old one - maybe I will adjust it a tad. Notice the diamond knurl. I don't have the cutters for that - straight and diagonal knurls yes, but not the 'inverted' diamond knurl. Rather nice, and easier on the hands...

Post war plungers, as I mentioned in my other post on the subject, are non-adjustable unlike their prewar forefathers, and because of this I think it makes sense to update them with an O-ring seal.

The hexagon reserve plungers are made from 0.600" 303 stainless steel hexagon bar. You'll need a decent length for chucking and for the milling operation. Chuck the bar with a couple of diameters showing beyond the jaws, to give you enough space to part off when you are done:

Turn the shank to the required diameter - a little over 5/16". This needs to be a loosish clearance fit in the tap body you just reamed.

Use a thin parting tool to form the O ring grooves. Space them so that they are at either end of the equivalent length of cork:

For those, like me, without a mill you can use the toolpost or a milling attachment to mill a 3/32" slot, about 1/16" deep in the tap shank. Since the loads involved in this operation are tiny, I didn't bother to set the lathe up for milling. I cut the slot at about 1500 rpm in two passes, with a 3/32" slot drill.

Once you have completed the milling, test the plunger in the body and make sure the plunger slides freely with the retaining screw in place. Next, put the bar back in the chuck and polish up the shank; then, before you part off, turn the shallow chamfer on the inside of the head. You can then part off.

Turn the plunger in the chuck, and skim the outside face of the head, cutting the shallow chamfer in the same setting. Polish the head and you are done.

And watch out - the reason that slot looks slightly ragged is because I broke a cutter in it. Go easy.

Next thing - you will want to smooth the edge of the ports in the tap. look at this:

See the sharp edges? Remove that with a burr in the Dremel, or a tiny grinding tool. If you leave it, the O ring will be damaged. Look:

That nick will cause a leak. You are not really supposed to use O rings in dynamic applications like this.

Thanks for reading, and I hope you found it useful.