Model A - painting

 In my quest to put the primary side back together to clear the decks before starting to investigate the forks, we come to a little painting job on the chain cover and clutch dome.

I've cleaned up the clutch dome with a 40 grit flap wheel, 60 grit paper, and degreaser.

This is the first coat of Tractol 816 grey primer supplied by Smith Allen to go under the Tekaloid 318 gloss black.

It goes on easily and dries very quickly but it does seem to hold brush marks and attract dust.

Twelve hours later, with a slightly larger brush I applied first top coat:

It goes on very nicely but I seem to have trapped quite a lot of bubbles. Perhaps I am over working the paint.

I put a second coat on the next day - after nearly 6 hours it was still slightly tacky. The second coat could be handled in 24 hours and these two parts are now hanging from the workshop ceiling to cure.

As everyone says, the depth of the gloss is amazing.

Model A - Primary chain

 Today I have fitted and tensioned a new 1/2" x 0.305" primary chain, which for the record has 80 pitches. If you recall, this bike has a new 23 tooth engine sprocket:

The 23 tooth sprocket I've fitted is the largest one Ariel offered in 1930:

This appears to correspond with an 80 pitch primary chain, though I'm sure 79 pitches would fit as the chain is nearing the end of the adjustment. Perhaps the 80 pitch chain is designed to suit the Burman clutch.

A 79 pitch chain would need a half-link which I believe are available from Simply Bearings. I might investigate that, but I don't fancy having two spring links in the chain.

Charlie's shed - adjusting primary & rear chains

 The Huntmaster clicked over 400 miles on a run recently and is bedding down nicely. Checking it over in the workshop revealed a front chain that was rather loose, and of course one of the issues that you learn when dealing with these old bikes is that if the front chain is loose the rear chain will probably be tight as sometimes the gearbox will move. 

It's time to have a look at both chains, and for this we will use the on board toolkit:

First stop is under the oil tank where we find the gearbox top bolt and the chain adjuster. Loosen the nut on the right a little bit and then use the chain adjuster to draw the gearbox backwards or push it forwards.

Next you need to gain access to the primary case so that you can inspect the tension on the primary chain and later top up the oil. If this is tight use a big flat spanner to undo the inspection cover:

Now you can see the chain. This should have about 3/8" up and down movement and this should be slack movement - the chain should not be stretched tight and you should not be putting much effort into moving it. If the chain is too tight you will be putting undue pressure on the engine main and gearbox bearings, not to mention the chain itself and the clutch basket bearing. Typically the chain will get looser as it wears and you will use the gearbox adjuster to draw the gearbox backwards by a little bit to tighten the chain. When you are done, leave the gearbox adjuster where it is and tighten up the gearbox top bolt.

Turn the engine over on the kickstart and test the chain in a couple of places to ensure it's not over tight anywhere.

Once the front chain is done, we can look at the rear chain. The Huntmaster has a fully enclosed rear chain case and the inspection point is behind a grommet which itself is behind the left hand side silencer. It's easiest to remove the silencer to gain access to the chain:

This is much easier on bikes with only a simple chainguard, but on this one we can enjoy the fact that the rear chain oiler is doing it's thing in keeping the chain clean and lubricated.

Once you can access the chain, slacken off both the wheel nuts and the lock nuts on the chain adjusters shown by the spanner in this next picture. When you tighten the rear chain you must make sure that both adjusters are turned by the same amount - count the flats - to make sure that the rear wheel alignment is maintained. Be really careful with this because setting up the rear wheel alignment is a bit of a pain. Do the lock nuts up when you're done and tighten up the wheel nuts again.

When checking the rear chain it's best to turn the wheel and sit on the bike, because a swinging arm bike will always tighten the chain when the swinging arm deflects upwards. Ariel recommend 5/8" chain movement with the swinging arm deflected to normal riding position and 1 1/4" to 1 1/2" with the bike on the stand. That's quite a difference and comes from the frame geometry - the swinging arm pivot is a long way from the mainshaft centre.

Model A - primary chain cover

 As I've said, probably more than once, the primary chain cover and it's associated parts - the clutch dome and dynamo chain cover - have a number of problems mostly associated with splits and broken welds. Nothing fundamental is missing apart from a couple of brackets and there's nothing we can't fix.

You've already seen that I've made a start on the clutch dome in a previous post so today we are going to start on the chain cover proper. 

The chain cover supports the forward end of the rear chain guard and the bracket for this has cracked and been repaired with a piece of thick sheet and several ugly rivets. Fortunately it has been fixed in more or less the right place:

What we will do, to start with, is retain it in this correct position with a short weld:

Next we will remove the rivets and start to reshape the bent and twisted metal. This is a simple as using a centre punch and a series of progressively increasing twist drills until the rivet head comes off leaving the stem still in the hole, when the part will come off with a little tweaking and no damage.

With that lower bracket removed we can dress out the distortion in the chain cover .

The next job is to make a new bracket in the style of the existing brackets at the front end of the chain cover. In common with those brackets this is cut from 2 mm thick steel sheet on the bandsaw, linisher, and pillar drill. Here it is in position for a trial fit:

It is supposed to fit inside the curve of the chain cover and be retained by two spot welds, the holes for which are still there. This is quite a weak design and I'm not at all surprised that the welds failed.

The new bracket needs a bit of bending to get it to fit properly at both ends.

That's it for this part of the repair. What you can't see is that I have made a short weld along the edge of the clutch aperture to retain the outboard edge of the bracket.

The last bit of this job is a split along the bottom edge which has opened out probably due to the stresses remaining in the part after it was pressed to shape. I've used three clamps to draw this together again for tacking:

This is not the most tidy job, but I realise now I had the current too low. I try to keep it down to avoid blowing through the thin metal but you need it high enough to make the metal flow! I laid too much filler rod onto this to make sure I wasn't burning holes.

It will grind out ok, and the penetration is perfect. 

Getting near the end now - two holes to fill. A thin copper backing lets you puddle in some filler rod:

I've not taken a picture, but with a copper backing there is virtually no dressing to do on the back of this weld.

Back to the rear chain guard mount again, with the rivets removed and the holes plugged we can just weld up the seam along the edge of the main primary chain guard:

This is a tiny little autogenous butt weld with a little bit of filler rod part way along.

That will do.

Quite a bit of cleanup though - we will do that tomorrow.

I'm calling this done.

Model A - work faces

 The Model A has been on the bench a while now and I've been spending time investigating what I've bought and reminding myself of the parts I've made or acquired over the last few years. 

As a man who likes to tinker in his workshop - who doesn't - various work faces have opened up as I've investigated the machine. 

One is the broken dynamo and it's clamp. Removing the dynamo I realised that I didn't understand how it was held in place with only half a strap - pleas to other club members soon yielded a few photographs showing the bits that were missing. 

Taking the dynamo off showed me quite how bad the damage was. Both of the end castings appear to be broken - the drive end is in two pieces and I had to drill out one of the screws, but worse, the armature is actually bent. It looks like it's been dropped on the floor or had a whack from something at some point.

For the record, the armature is 157 mm long and you can get new ones - Feked have them.

The secondary of investigation is all of the tinware on the drive side. I started with the clutch dome but I have various repairs to do to the primary cover and the dynamo chain cover. 

This led to me looking at the clutch and the gearbox because of course the aperture in the primary cover dictates the movement of the clutch to some extent during the tensioning of the primary chain.

Thinking about the gearbox and it's range of adjustment led me to the gear controls, most of which I have already made. This leads naturally to the fixing of the fuel tank because of course unless the fuel tank is firmly bolted down (and I have new rubbers for that) the gear controls can't be set up. 

If that wasn't enough I've been looking at the front wheel and loosening the spoke nipples. I'm not going to go any further than that though - I was trying to establish whether the front wheel rim could be used or whether it was too far gone. 

The other area I've been looking at is the Lucas H52 headlamp, it's shell, and the mountings. The shell was quite bent and whilst I had the hammers and dollies out to sort out the clutch dome I knocked the dents out of the headlamp shell. It still wouldn't sit straight - it's aligned to the offside - because the mounting bars are also bent...

I think that's enough for now. I promise that I won't take anything else to pieces except perhaps for the gearbox outer cover - the kickstart doesn't seem to work and I can't get first gear!

Model A - primary chain case tinware

 Moving on from the clutch bowl, our tin bashing activities come to the primary chain case. This is all present and mostly correct but some of the brackets and appendages have been broken and repaired by riveting. 

One thing we mustn't forget when we view this overall shot is that the position of the gearbox rather dictates the position of the primary case in that the primary case aperture for the clutch must accommodate the full range of movement of the gearbox. 

We must also think about the bolt hole for the rear upper chain guard. 

Again this position is dictated by something else - in this case the rear bolt for the chain guard which is fixed to the luggage carrier.

However we can take comfort from the fact that the holes for the foot rest bar, the brake lever and the shock absorber grease nipple at the front are fixed positions, so we can probably weld up the lower rear bracket without too much worry.

 The secondary cover, which protects the dynamo chain is present and in more or less sound condition - it's only missing one of the feet.

The stripped 1/4" CEI stud in this position came out very easily. The bracket is a little bent.

Here's that missing foot:

There's plenty to sort out here!

FH - engine sprocket

 With Mrs H on the couch, asleep after a busy morning on the allotment I decided to do some shopping and on the way back get a bit of time in the workshop. After finishing measuring all the timing cover screws I decided it was time to change the engine sprocket.

Regular readers will know that I realised after riding the bike that the gearing was very low, and inspection of the pictures revealed that I had a 22 tooth engine sprocket: for solo use, I should have a 24 tooth engine sprocket. The Siamese pipe that came with the kit is another clue to the bike's history with a sidecar!

Pulling the primary case apart is a pretty straightforward exercise, if messy. I thought the case was empty of oil, assuming it had all been thrown out - in fact, the drain hole was blocked with red Hermetite and removing the plug had no effect - so it all ended up on the bench...

The primary chain has 74 pitches. A lot of adjustment of both chains had the gearbox in a suitable position for the new sprocket to go on. Note to self - for the future, using a socket and the slim plastic 3/8" ratchet drive on the primary chain adjuster makes it relatively quick to move the gearbox. 

Here it is in place:

I noticed that at some point in the dim and distant past the primary chain must have got very loose because the cast lug for the primary case screw right under the sprocket was very worn to the extent that oil would leak into the screw hole. I refitted the screw with a fibre washer. Incidentally, rather than use the large gasket with Wellseal I sealed the primary case with Threebond 1215 and no gasket.

These things are so easy to work on. I'd been considering whether to tackle this job before I rode the bike again thinking that I didn't want to have it off the road for too long but actually this kind of thing only takes a couple of hours. I hate to think how long it would take on a modern bike - but then you probably wouldn't have to do it in the first place! 

That's it all back together again a couple of days later:

FH - small repairs

 Spring is here and I'm away using the Square Four for some little house renovation jobs in a nearby town. There's a little bit of time in the workshop to do a few bits on the Huntmaster. 

We'll start with blocking that hole in the primary case that used to be used for the chain oiler before the fully Enclosed Rear Chain Case arrived. It's lost its blanking plug so I've made a new one up from a cheese head 3/16" BSW screw with a fibre washer:

The next one is a bit more serious. This is the pinhole in the fuel tank - I've taken the tank off for better access which is quite easy with these single centre bolt tanks. I've opened the hole up a little bit to clear the paint with a scriber and I've cleaned the area with acetone.

I've put a blob of Seal-All in that hole - just a tiny blob. After deliberating for a while over the approach I would take to this repair I realised that Seal-All had been sealing several holes in the W/NG tank for many years, and is still good. We'll see how this turns out tomorrow.

FH - toolbox, charging and other progress

 The toolbox is back on:

In other news, the primary case now has oil and the FERC is no longer dripping oil all over the bench. The oil tank now has a felt wick for the chain case feed:

It's made from a strip of felt, 10 mm x 10 mm x 25 mm:

I made this short video to record the fact that the battery is now charging after we re-polarized the dynamo and updated the RB108:

Doesn't the engine sound great! I got it started a couple of times using Easy-Start, but it only ran for a second or two. Playing around with the fuel supply, I eventually tickled it for a long time - until I had a flood under the carburettor. It started and ran perfectly, but needs choke - perhaps I am starting to learn the technique?

To report on a couple more things: the clutch cover screws are a bit short of thread - there is a 1/16" unthreaded section under the head - cutting the thread on that bit will allow them to go fully home. I've put shake proof washers on them for the moment.

I've failed to improve the front brake - any more turns on the adjuster just lock it solid. It will have to come apart.

The oil banjos on the rocker box are in good shape - they have a lot of contact area though, so they have to be very tight to seal. I've smeared a bit of Wellseal on them which seems to have done the trick.

Number plate next, then the instrument panel and lastly the fuel tank.