Model A - rear brake pedal

 The rear brake pedal shaft is one of those areas where you see the horrors perpetuated on old motorcycles through years of neglect and changes of ownership with varying levels of skill. Having removed this one to rebuild the footrests and replace the brake pedal spring we realise that it is in fact a bit mangled.

To start with, we can see that the thread has been cut to a BSW form - Ariel would not have used BSW here, the thread would originally have been CEI. We will build it up with weld and cut a new thread to the right size.

That pin across the right hand end as we look at it forms both the stop and the fixing point for the end of the spring. Part of it, the fixing point for the spring, has broken off. It proves impossible to knock out though it is listed in the parts book as a separate component, so we drill it out.

Here it is, illustrated in the 1930 parts book:

The other curiosity which I didn't understand initially is how the shaft is lubricated. There was no obvious grease nipple but under all the gunge a hole appears half way along the shaft, which is clearly to let grease into the central reduced area - and an ex-nipple on the end which has had some attention from a hammer.

I've said many times that the AOMCC is a wonderful club to be associated with and a few questions posted on the Facebook page yielded this drawing from 1925 and signed by Val Page himself. The drawing clearly shows the same formed nipple on the end of the shaft that the later Ariels used until the end of four-stroke production in 1958.

The difference between this and the later bikes is that whilst the later bikes use a nut to retain the brake pedal on a parallel fixed shaft, this application uses a nut on a taper to retain the pedal on a rotating shaft. Therefore when you want to remove the pedal for adjustment, you have to undo the nut and knock the end of the shaft to free the taper. Guess what happens? The nipple gets flattened...

To start with we're making a new pin on the lathe. I didn't intend to use a piece of stainless, but at the time I couldn't find a quarter inch piece of mild steel round bar - but no one will ever see this, so it doesn't matter if it's the wrong colour.

I've cut a semi-circular channel in the end of the short bar to locate the brake pedal spring. It's a simple matter to chamfer both ends and press it into the pedal shaft.

This is how it looks.

This is apparently the correct spring - I got it from AOMCC Black Ariel spares some while ago and I'm assured it is the right one, though it looks very stretched when it's in position.

See what I mean?

The next step is to build up the mangled thread and nipple. This is none too tidy but hopefully there will be enough material to turn it to 7/16" without firing up the TIG set again.

The first pass at turning to size shows, as it often does, that more building up is required:

That done, we can start forming the shapes according to the drawing with a radius tool to form the curve and shape the grease nipple:

I seem to have missed out a step here - I've forgotten to photograph the drilling out of the grease hole, which is 5/32" per the drawing. The next step is to cut the 7/16" CEI thread. 

Here it is on the bike with the brake pedal attached:

We will need to be very careful when moving the pedal - using a socket or something over the nut to avoid damaging the nipple!

Here's an overall view. That pedal is very high!

Model A - sorting out the footrests

 The footrests on the A are a bit of a mess. One is thoroughly non-original and is probably homemade, the other has been shortened radically, to the extent that it is useless. Also in this region - the spacer between the engine plates (that prevents tightening the footrests from squashing the engine plates) is missing, the brake lever return spring is missing and the brake lever spindle has been recut with a BSW thread - it has obviously been stripped at some point.

Ariel footrests don't change much and I have a new set from club spares:

The rod is bent, but worse the threads are worn on one end and recut to 7/16" BSW. I've got a large piece of stainless steel to make a new one. In that package of spares was a brake lever return spring.

The two footrest supports were also bent but a few minutes with the MAPP torch sorted that out:

Next, we need a bit of time on the lathe to make the spacer that goes between the engine plates. We'll use the manky foot rest to provide the material: 

With the power feed on, it doesn't take long to clean up this bit of bar:

It's turned down just enough to fit inside the brake lever spring, bored 11.5 mm to clear 7/16", and parted off at 2" long. It's lightly chamfered at both ends, inside and out:

So that is that for the moment. The bar is a little bit long and one of the nuts is very loose and needs replacing, but we will sort that out when the rear brake pedal shaft is finished and it all comes apart again.

Model A - dynamo engine plate covers

 There's a lot of splits in sheet metal components on this bike - not surprising after 95 years of corrosion & vibration. This is the top engine plate cover over the dynamo, and one of the bolt loops is missing. I'm replacing it with a bit of sheet cut from the side of a dead dishwasher - 0.5 mm thick:

One of the benefits of having quite a small TIG welder is that you can do tiny little things like this - this was set at 15 amps:

This is the front engine plate cover. Despite the fact that the one in the parts book is slightly different (it has four bolt loops) it appears Ariel modified this part without reflecting the change in the parts book illustration - I'm saying this because others I've seen are the same as mine - go and look at the one in this post, about the dynamo clamp.

FH - frame & fork bits

 Lots and lots of little jobs today. I've put the front wheel back together and back in the bike, noticing that the centre stand is off the deck when the front wheel is high enough to come out - I used the scissor lift to get the bike high enough; that centre stand is going to have to come off again.

There's a separate post on the work I've done on the fuel tank, but there are some other bits to talk about here.

These 2 BA screws hold the front engine plate cover in place - I must find a better way of holding small screws for trimming:

Doesn't that look nice:

By the way, I used a small flap wheel to clean the paint out of the front axle clamp hole:

W/NG - Assembling the bottom end - again...

So, a bit of spare time arrives and I have the camshaft, the cam bush, a 3/4" reamer and a gasket set. Let the bottom end rebuild commence!

First, it's back to the Rothenburger to remove and replace the bush, which I can do in one heat cycle. I'm careful to avoid the new bearing. I knock the new bush into the hot cases, driving the old bush out as I do it - a simple operation when you have enough heat.

Whilst that is cooling, let's look at the camshaft. The principle reason for replacing the camshaft is because the inner journal is badly worn. I reached out to the AOMCC Facebook community and came up with this camshaft, which is actually the profile used for the sidevalve machines. You can see it has a much longer duration than the Ariel F cam normally fitted (the one on the right), but it has the same base circle diameter. This means I will get more fuel in and and exhaust out again, and make more power but I won't have to change the followers or the pushrods.

Another problem solved by the AOMCC is the knackered half time pinion, the one at the front of the picture. A member kindly sent me the one behind, which looks unused.

Coming back to the crankcase camshaft bearings which I fitted earlier. When you buy a bush it is usually undersize, and this was no exception. It needed reaming to size, whilst aligned with the bearing in the timing chest - so I used the timing chest bearing as a guide whilst reaming the crankcase end bearing. In this next picture I have the timing chest bolted in place and a 3/4" round bar passed through both bearings to demonstrate their alignment - the bar turns smoothly and freely.

This next picture shows a block of wood I use to support the crankcase whilst working on it. The cam follower pin, crankcase nose etc. fits in the hole.

Before I assembled the engine, I fitted the camshaft so that I could prove the bearings. The camshaft turned smoothly and with no wobble, so I proceeded to dismantle it all again and to assemble the crankshaft into the cases, and to bolt the cases together.

I replaced the assembled cases in the frame and assembled the engine plates. Now that I had the crankcase held securely, I refitted the oil purifier with some Loctite 243, as suggested by Chris Williams at Alpha Bearings. A lot of folks really struggle to get these out and they often come out in pieces; I have had this one out before (and cleaned it before), so it was quite easy, but I was surprised to find it had quite a bit of sludge in it. Chris's point was that they might be difficult to get out, but if they come out when the engine is running the crankcases will be scrap.

Once that was back in, I took the opportunity to use the oil can to pump some oil into the end of the crankshaft, and eventually I saw it emerge around the big end proving that the oil ways were aligned.

Now, I could fit the new half time pinion & camshaft and set the valve timing.

I had a look at the cam followers and selected the best two. The inlet one is quite worn and I should really replace it.

Before I put the timing cover in place I need to fit the magdyno. Before I did that, I cleaned up the slip ring which was a bit mucky.

Here's a new felt seal for the magneto drive:

Next, I fitted the timing gear case with it's small gasket, and added the large gasket with Threebond 1215:

I fitted the timing gear cover and rotated the engine several times to ensure the new gears were quiet and free, adding the camshaft magneto sprocket and the magneto chain, nominally tensioned at this point. I'll finalise that when the barrel is on and I can set the timing.

Since we are nearing the end of activity from this side of the bike, I'll refit the mudguard bracket to the engine plate. The original bolt fitted here looked like it had had an M8 nut forced over a BSC thread, and both were scrap. This is a new stainless 5/16" bolt & nut.

With that done, I can fit the oil tank, hook up the oil lines and fit the oil pump.

Next, I need to clean and paint the barrel, fit the barrel & piston and set the ignition timing. Then I will close up the magneto drive having set the chain tension; I'll then inspect the clutch before I finish building the head. I know that I have to make a valve guide drift and paint the head, and possibly give the valve seats some attention - I'll do that while I wait for the clutch tab washers, nut and any other components I find damaged.

W/NG - Magneto Platform Repairs

The AOMCC forum is a wonderful place to learn stuff about your bike. A while back, I fixed a broken lug on the W/NG timing case which supports the magneto platform; the magneto platform is a steel plate welded to the offside rear engine plate down it's centre line, so it needs support to resist the tension from the magneto chain.

You can see it here, roughly assembled to my crankcases:

What I didn't realise, and what I learned from the forum is that the platform is supported at the other end as well, by a bolt through this hole - which was missing. I had a look through the hole, but as predicted by the forum members the lug into which the bolt screws was also missing - it's spot welded to the plate, so it probably wasn't a very meaty lug

You figured out that this picture shows the same assembly but upside down, right?

So, we have the engine apart so we will make a new one. This is a bit of scrap steel, about 4 mm thick and maybe 20 mm x 15 mm. I've marked a line down the middle where I want a tapped hole 1/4" x 26 CEI.

I've put the plate behind the hole, so that my marked line sits in the middle of the hole. I'll hold it here and scribe a line in the paint around it.

Using the scribed line, I dot punched the corners of my lug position before removing the paint with the Dremel. The dot punched holes let me see the position after attacking the surface with a sanding wheel. I'll clamp it in place with a toolmaker's clamp:

Then, we have a dose of TIG at 60 A. It's a thick bit of plate so it needs a lot of current - it also needs a lot of stick-out as it's a bit awkward to get the torch in.

Now, after cooling and cleaning up on the wheel we can repaint the plate. Then we have to assemble the plates into the frame with the crankcases:

With it all bolted up, we can mark the position of the tapped hole through the other plate using a scriber:

We can pull the plate off leaving most of the assembly still together, and we find a neatly marked hole which can be drilled and tapped:

Next, I need to remove the crankcases and put the main bearings in.