Model A - front forks dry build

 You might remember from the recent girder fork investigation post that we had a lot of movement in the forks - in fact a 3/8 inch variation in wheelbase. It was obvious that a lot of this was down to wear in the links and wear in the spindles.

I contemplated reworking the original links for a while but while chatting to the AOMCC Black Ariel spares specialist I discovered that reproduction links were available from the club at a good price, so bought a set. They're not perfect - for example the middle links are smaller in diameter than the originals so I will keep the originals and repair them at some point.

For some reason the top links on the 1929 and 1930 bikes are not fully threaded:

The club spares officer also recommended I bought a new spring. It's certainly true that old fork springs I've used in the past have been very soft and looking at the old spring previously it was clearly a bit stretched. Again new ones are available at a reasonable price:

Putting these bits together with the old spindles revealed a significant reduction in play.

A few days later, the new spindles arrived from Acme Stainless - and very nice they are too. On bikes of this era, you don't need the knurled washers - these arrived in 1934. I bought a pair of headstock nuts as well since I was one missing and pulled up the steering head bearings a bit more. 

Putting all these in place removed all of the play in the forks. I now cannot detect any variation in wheelbase.

Stuck in the steering column there is the beginning of the blanking plug that is used on the Model A which was not supplied with a steering damper.

That plug will be chrome plated eventually. I'll finish it machining it long before that happens!

Model A - magneto

 As usual, I will be using the services of Mr Tony Cooper of Halesowen to rebuild the magneto for the Model A. I spoke to Mrs Cooper today and learnt that Tony would be able to rebuild the BTH KC1 for me. He's done the magnetos for both the FH and the W/NG, and they are excellent - the estimate for the Model A was a maximum of £250 and it would take 14 to 21 days.

This is how the magneto looked when it arrived. It's more or less the right period for the Model A but as you can see it is a slack wire advance magneto - Ariel specified a tight wire advance magneto. In theory, slack wire advance is a better option because if you lose the cable, the engine will still run optimally at speed - but it might be rather hard to start!

First job then is to remove the magneto. Fortunately this side of the engine is relatively clean and it's quite straightforward - it's just the same arrangement as the W/NG, built 12 years later.

Underneath I was surprised to find only two bolts holding the magneto down - the magneto is set up for four bolts, the W/NG uses three. 

With the magneto chain cover removed we can have a look inside for the first time, and it's all pretty familiar and pretty clean although the chain is very loose indeed:

All you have to do is remove the magneto retaining nut and then use the usual magneto pinion puller to release the taper:

You can then remove the two bolts holding the magneto to the platform and lift it out of the way. There appears to be a seal between the magneto and the chain case which looks like it is a felt seal sandwiched between two pieces of tin - it's black and oily at the moment so when it's cleaned up we can have a proper look.

Here are a couple of before pictures of the Magneto after it's had 15 minutes of fame in the parts washer:

Looks pretty good and turns easily. There's something wrong at the points end though - the bolt retaining the points to the armature makes contact with the brass end cover. One of these parts must be wrong, probably the end cover because in this arrangement the magneto will always be earthed and will not spark. 

Tony Cooper will sort all this out!

Model A - front stand

 Whilst working on the forks I made a little side project out of the front stand. Whilst I have the forks in bits I want to make sure that the mudguard and it's stays are all in the correct places, which of course includes the front stand and it's fixings. Sorting that out will also allow me to trim the front mudguard to the right length

We have the original front stand with the Model A, but unfortunately it's rotted out. I always seem to end up welding these stands for one reason or another, and this one is no exception - the stand retaining clip is missing as well.

I've had some suitable heavy wall tube knocking around since the FH project which needed its front stand extending by about an inch. It's a blessing that Ariel didn't change their design every 5 minutes and the stand material used here is the same as is used on all my other bikes - consequently there's about three feet of suitable tube in the material bin that I can use to fix this stand.

I use the Rothenberger Superfire 2 blow torch to make freehand bends using the old stand as a pattern and eventually end up with a complete bottom section that I could weld to the old arms

The linisher is very useful for squaring up joints in tube work which in turn makes a very straightforward autogenous butt weld:

Before we go any further, we need to make the clip at the back of the stand to position it in the right place to get the arms the right length and in the right orientation. This is the clip on the W/NG:

I've made this out of a piece of 16 gauge steel sheet cut to a strip around 1 in wide and I've drilled a 1/2 inch hole in the strip to receive the annular part of the special nut which is used to retain these stands. I folded the strip in half and cut a slot to clear the 5/16 inch bolt to which the stand is fastened.

I made a few of these special nuts on the lathe some while ago, probably for the WNG. The Model A was in the pipeline at the time and I knew I would need a few:

I've used this electronic level and some pictures provided by fellow club members to set the stand in the right place to determine the position of the hole for the clip:

With the hole marked and drilled, and the mudguard cut to the right length, I fixed the new stand section in place with the new clip:

With the bottom section in the right place, I can measure the length of the arms and tack them in place:

It's a very straightforward job which finishes this area ready for paint.