Thursday, 30 May 2013


I use this spreadsheet to manage my parts, track what I need, what I've ordered, what I paid or budgeted for the rebuild...

The parts are grouped by work package; can be filtered or grouped by vendor, order status, part number, or whatever you want.

Very useful. Here it is:

Thursday, 23 May 2013

Resting my weary feet...

Working around the oil tank & oil lines, I need to be sure that everything in that congested area is in before I can say I've completed work for Phase 1.

Fitting the footrest mounts in place, it is clear we have a few problems though they are easily fixed. These type of issues demonstrate clearly why a mechanical - only rebuild is necessary on a bike which is in pieces.

Take a look at the picture of the RH footrest hanger - it is clearly pointing to the rear of the bike and has perhaps unsurprisingly been bent at some time.

The left hand hanger, the one that passes through the primary case is nice and straight (it is a new pattern part) but unfortunately the anti-rotation lug on the engine plate does not fit in the cut out machined for it - easily fixed with a file, but not something you would want to find when it is just back from the powder-coater. And remember the Bantam fork legs - powder coat, if that is what you are going to use, is very thick and we will need extra clearance adding for the thickness of the paint.

Here's that footrest in a better place, after a session with the Rothenberger. We also have a clutch lever boot, making it's first appearance on the blog.

Easy job - grasp the end in the vice using the handy bolt hole, and heat the area you want to move to cherry red. Use a stout tube, Stillson, ring spanner or whatever suits your purpose and you can heave it back into place - don't hit it, bend it gradually using all your He-Man (Master of the Universe) strength and if you have it hot enough it will move easily and in a controlled fashion.

Let it cool, trial fit, go through the process again if necessary.

Oh and by the way - the other valuable lesson I learned was that no, the footrest rod spacer won't go in if the engine is in. One for the future, that one.

Sunday, 12 May 2013

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 - you palm will do. This will raise the edges of the gauze around the former. You can finish that off with you 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:

On with the Oil Tank

Looking back, I realise that pulling those dents out cold was never going to work. The last time I did something like that, I welded the pins in and pulled the dents out hot.

Ho hum. With cracks like this, there was no going back:

So now you are all going to find out what the oil tanks looks like inside...

I decided to do what I should have done all along. Using the trusty hacksaw, I cut down each side of the damaged area. Using a cut off wheel in the Dremel, I cut a short slot, long enough to allow a hacksaw blade to pass through, in the long edges of the damaged area. Then I used a hacksaw blade to remove the damaged area:

The tank is made of 18 SWG sheet. So, taking a piece of cardboard, I cut a template roughly the same size as the hole and attached a loop of masking tape to it. I folded the edge of the card to allow it to fold around the edge of the tank. I then suspended this in the hole and drew around the inside of the hole, onto the card. I now had a card model of the repair patch I would need.

The shape was then transferred to a piece of cold rolled 20 swg sheet, and cut out with the Wiss aviation snips. I folded the edge in the vice, and then used some scrap material to press the joddle into both edges, so that the pieces would sit flush with the original surface:

I've shown it here, held in place with magnets. At this point it is important to dress the edges of the tank, take out any wobbles or dents and make sure that patch sits flat. This is not good enough:

All adjusted; and the butt joints at the short sides have been given a 45 degree weld prep. The panel is tacked in place with the MIG:

Fully welded. a bit messy in places, but I blame the lighting. The lights in my shop are either behind me when I am welding (so I am welding in the dark, with the lights shielded by my body), or if I switch the overhead lights on the sensor in my helmet picks up the brightness and darkens the lens - welding in the dark again:

Dressed with the flap wheel:

There was another weld/dress step as I tested the tank. I filled the tank with water (after it had cooled) and found several holes; these were welded & dressed; I now have two very minor holes left, but the family are complaining about the noise the grinder is making so I had better stop.

Sharpie rings mark the holes!

A couple of days later in a marvellous week at home - I have not travelled anywhere and I have the luxury of a wonderful wife who brings me Martinis in the evening - I'm done with the oil tank. It has taken two more leak test/re-weld/grind cycles to get the tank water tight, but now the repair is invisible as the day the tank was made.

A temporary coat of black hammerite, until we are ready for Phase 2, and we are finished.

Monday, 6 May 2013

Shrinking & pulling

After the gearbox was back in, I decided to have a bit of an interlude and sort out some of the fabrication jobs that had been knocking about.

Finding myself with a spare hour or two one day, I made a start on the dent in the oil tank. The tank has had a major league ding in it for some time. Some was on the AOMCC forum suggested it may have been a battery explosion - it looks more like someone has used it for target practice.

Taking inspiration from a good book 'Building Budget Brits' I decided to use a method involving brazing & pulling to remove the myriad of dents in the tank. Some of them were very deep & localised, clearly with a lot of stretching going on. Now I could have filled or lead loaded this tank and avoided all the work, but I'm keen to learn and try new things....

So the idea is, we pull the dent out without holing or cutting the tank by fixing a suitable stud, wire, piece of scrap to the bottom of the dent and pulling it outward. I'd hoped to be able to weld to the tank and to pull the dents out with the tank hot, much like I repaired the breather tower. However, I was a bit concerned that I might just end up holing the tank, weakening the area around the weld and pulling or tearing the material.

So I elected to braze plain steel nails into the bottoms of the dents and pull them out cold. This would be OK, because during multiple brazing operations the material would be annealed several times. Then, I put a steel bar across the panel being worked on, to act as a fulcrum for the pulling operation. I used a pair of combination pliers to grip the nail and pull the dent out.

So here is the first pass

Nails resited, here we go for the second time..

and a third attempt

and again - four times now...
So before the fourth attempt, we had created several 'peaks' to go with the considerable troughs already in the tank. Levelling the peaks gave us an opportunity to lose some of the stretched material, by locall heating (bright red) in the area of the peak and reducing the height with some light hammer blows.

This is almost at a stage where we could use some filler... Lead maybe...

But, reasoning that this was going well and I could get more of that dent out, I pushed on with a fifth go at shrinking & pulling. This was lower but more level until i cleaned the flux off and I realised the 50 year old steel had cried 'enough'! Take a close look at the picture and you'll see a lot of cracks have appeared:

I think that this is due to hardening. Of course, annealing or normalising steel has a time element to permit removal of stress and changes in the grain structure and of course cooling this thin material happens very quickly. Added to that, the material was obviously thin from 50 years of corrosion.

Max was very concerned: