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.

Oil Strainer

As I said in my previous post, I still have welding to do but it is time now for something quiet. 

This is the oil strainer banjo bolt out of the bottom of the oil tank. You will note that the strainer is conspicuous by its absence - only a scrap of solder remains:

A strainer is a simple affair made from brass mesh - I selected some from an eBay shop at 40 wires/inch to be suitable for filtering bricks, flies and sweet wrappers from the cold viscous oil in the tank.

Strainers are easy to make. Select a former to match the diameter of the banjo bolt - I used a piece of chromed tube intended for making clothes rails. Pass it through the hole in the tank, and measure the maximum length of the strainer. Subtract the length of the banjo bolt.

Cut a piece of gauze to that length with your snips, or use scissors. You need good quality snips - scissors are fine. Loose or worn snips will just allow the wire to slip between the shear blades. Cut the width to wrap around your former and add 3/8".

Fold up 3/16" or so at each edge, shown in the photograph above. One edge must go up, the other down, as shown in the first sketch below. Wrap the gauze around the former so the edges overlap, shown in the middle diagram.

Ease the folded edges over one another with your fingers, so they lock together like the last diagram.

At this point, check the strainer fits over the solder area on the banjo bolt. If it's OK, find a suitable mandrel (I used a cold chisel) that will fit inside and press the seam tightly together with something hard & smooth (like the shank of a screwdriver)

Now you need to make the end. Cut a disc of gauze, about 3/16" larger than the former you used to wrap the gauze. Lay the disc over the end of the former, and press it into something soft - your palm will do. This will raise the edges of the gauze around the former. You can finish that off with your fingers. The aim is to make a little 'dish' of gauze.

When you've finished, set it upside down in the strainer (raised edges upward):

This is how it looks all together:

Next step, solder it up. Start by taking the strainer off the banjo bolt again. Use a small torch to heat the large banjo bolt, with some Baker's Fluid in the solder recess at the top. Tin this area with solder when it is up to temperature. Use ordinary plumber's or electrician's solder for this job, there is no point in using anything stronger.

When this is complete & cool, mount the strainer back on the banjo bolt. Use a big electric iron and some more Baker's Fluid to reheat the solder at the top of the banjo bolt and it should flow happily into the gauze. Now, after the bolt has cooled move the banjo bolt in the vice so that the strainer is horizontal and the seam is uppermost. Take your soldering iron and run a small amount of solder right along the seam. 

When it is cool again, have a look inside the strainer and make sure it is clean. This area is for CLEAN oil and goes direct to the oil pump - you DON'T want any gobbets of loose solder in there!

Fit the end cap, and dunk it in some flux. Use the soldering iron to run a small amount of solder around the end cap, fixing it to the barrel of the strainer.

Let it cool, and wash the flux off.

And this is the finished article:

Very Flat, Norfolk

We can muse over what the oft-quoted Noel Coward meant by this line from 'Private Lives', which premiered at the Edinburgh King's Theatre 1930. However, keen observers and students of geography will know that Norfolk, whilst undeniably low lying compared to some parts of the country is positively undulating when compared to others, notably the Fens, at least in places.

Undulating is also a word that could be used to describe Amelia's sump plate, which won't be doing any sealing anytime soon:

Anyone got a spare one?