FH - Building the forks: a false start

As you might have read, after a prompt from the guys on the AOMCC FB page I bought some new stanchions, and very nice they are too:

Build it right, build it once I say. Here are some pits in the old ones and they will destroy the seals very quickly:

These are the original seal holders - they are supposed to be shiny chrome, and someone has cut them shorter for some reason. They are junk now.

I bought these seal holders on eBay - they are plated steel, and are very solid. They came with a set of springs (not the nice progressive springs in the background) for £65, so I thought I had a bargain; the seals themselves are standard lip seals, about £5 a pair.

I put them together with a new set of Draganfly bushes.

During that build I found the first stumbling block: the seal holder tool didn’t fit in the holder.

I needed to turn the tool down by around 2 mm on the diameter. To get it in the lathe, I had to make a plug so I could steady the end with a centre. The tool is too big to go in the fixed steady.

So now I could put the forks together…

End plug and bottom bush:

Here’s the next problem, and it’s Game Over. One of the seal holders is fine, but this one has the thread out of square with the stanchion axis:

So, they were returned to the seller, and replaced with these from Draganfly. They are beautiful.

FH - Preparing for assembly

 One of the nice things that arise from a dedication to one make, one era or perhaps just motorcycles manufactured in one country is a collection of specialist tools. Today, I'm quietly cleaning paint out of the threaded holes in the frame, yokes and swinging arm with CEI taps, while I wait for other bits to arrive and for the rest of the painting to be finished:

The fork stanchions have arrived:

And we have new seal holders, seals and progressive fork springs:

FH - Forks, Steering Damper & Swinging Arm

 A few spare minutes found me progressing the build a bit further. Last night I ordered the engine parts from Draganfly; the pistons and big end shells have already arrived from the AOMCC Twin Spares chap. They look excellent:

You'll recall the swinging arm has solid bronze bushes in place of the standard metalastik bushes, so the first job is to fit an angled grease nipple pointed away from the FERC:

The swinging arm goes in easily and is bolted very loosely. It's held up with an old shock.

I've put the steering damper back in; the pin tapped in easily.

Now, I was careful to ask the painter to avoid grit blasting the oil tank, and he has indeed prepared that by hand. However, the fork sliders would have benefitted from blanking off as they are full of grit; I made this swab to clean them out:

Running paraffin down the slider in the cleaning bath I swabbed the grit out:

There's quite a bit - that was worth doing:

I cleaned the fork legs with 180 grit Scotchbrite - they are not very good:

I ordered a set of seals and new seal holders yesterday. At £115 a pair, it's worth buying a new set of hard-chromed stanchions as well.

FH - Steering Head

 Now that the frame is on the bench I can start to assemble some of it, bearing in mind that I must leave mating parts for the paint to fully cure.

I start by reducing the height of the lift so that I can easily get to the head races in the frame, to clear out the paint and primer with a knife, scraper and emery. This is pretty easy as the paint is relatively soft, not like powder coat.

Next step is to clean and fit the races, which go on easily with a copper mallet and a tubular drift. Then it's 1/4" ball bearings, 20 in each race according to the parts book, retained with grease. There usually appears to be a gap where you could fit one more ball, but you should always go by the parts book - the gap is there to allow the balls to move freely.

The top race is easier to assemble, since the inner retains the balls:

Ariels have a dust cover over the top race. You'll note that I haven't fitted the grease nipples to the frame - I will, but all they do is allow the frame tubes to fill up with grease. There is nothing apart from a missing felt washer to direct the grease to the bearing; the washer is shown in the front fork diagram in the parts book but doesn't appear in the parts list.

Next, you have the rather precarious activity of bringing the lower yoke up through the steering head  and through the top race, hopefully without disturbing the balls. Sticky grease helps, as does a dry fit of all the parts. Remember that the top inner race fits tightly around the steering column so you must remove the paint from the fine thread, making sure the adjustment nuts fit:

Next we will go to the other end and fit the swinging arm. It's not obvious, but this is a time when the bike lift is very useful - you can do all this work at the most comfortable working height.

FH - Painting Update

The blog has been a little quiet lately, as the frame parts are at the painters and I have the engine in pieces - but more of that later. 

Pictures from Damon at DJ Spray Services reveal that the painting is on the way - these are the parts in Damon’s shop, just back from the blaster:

Damon has prepared the oil tank by hand - it’s not been blasted. He’s sprayed on the first coat of epoxy primer the same day as the parts arrived:

Blasting has revealed a few problems, the worst of which is these holes in the already lined tank. There’s a crack in the front mudguard, and two broken welds in the number plate:

A couple of days later, much of the black is done:

I retrieved the damaged bits to bring back to the workshop for repair:

Straightforward for the most part, except for this old braze repair which won’t weld. Brazing with TIG is possible with the right rods (with no zinc, and is technically bronze) but repairing this produces lots of spatter and white zinc oxide. It pressure tested perfectly well after a few attempts.

Returning the repaired bits for painting, I picked up the black parts which were ready packed:

They need a while (months) to cure, so they can sit on the bench while I build the engine:

FH - Engine bottom end

 While the painted parts are away, I've got the engine on the bench. Way back when, I established the state of the bores, mains and big ends and what I want to do now is to trial fit the new large bearing crank into the original cases.

A little while in the kitchen at home saw the main bearings fitted:

It's then no more than an hour's work to assemble the crankshaft and the timing gear; the good news is that the timing gear bushes already in this case are in very good condition with very little play. Shame I already bought a new set.

It was clear that the crankshaft was a bit tight. The setup with the DTI reveals no end float and the crankshaft was mildly stiff to turn, but then it does have a large plain bush at one end:

Investigation revealed that the drive side bearing wasn't fitted fully home against the crankshaft web. With that fixed, we have 0.34 mm end float:

That's about 0.013"; we want a maximum of 0.005", according to BSA Service Sheet 208 - Waller is silent on the subject. Since 0.005" is 0.13 mm, we need to shim 0.21 mm; I've bought 0.25 mm shims which should give us 0.09 mm end float, or 0.003".

More later when bits arrive.

FH - Prepared for paint

Here are the pictures of the Huntmaster bits that I'll use to catalogue the bike for the painter: