Model A - brake plates

 There hasn't been much action on the Model A lately – I have been rebuilding the top end of the Huntmaster and doing a bit of travelling. However, here is a little interlude: some while back we painted the brake plates from the Model A ready for rebuild and last year I acquired a new set of brake cams from the Slovak Klub.

You can see from the picture how bad the originals were - there was an awful lot of movement in the bush on the brake plate. Karol at the Slovak Klub supplies his replacement cams with a diameter of 13 millimeters which I thought was a problem until I realized what he was doing – if you drill out the brake cam bush on the brake plate, 13 millimeters is enough to take out most of the wear and you can fit new brake cams without replacing the bush, which saves a bit of time.

They work very well, although the square section is a bit oversize too - probably intentionally!

I had also noticed that whilst Karol's cams were identical, the old ones were not. You can see from the picture of the rear brake plate as the bike arrived that the position of the brake lever is a long way forward - too far forward:

The new cam puts the brake lever in a more sensible position.

Model A - painting more bits

 A rewarding but seemingly never ending job is painting bits for the Model A. The wheels are off and the brakes are currently in pieces and here we are with two brake arms and the torque arm for the front brake.

These are the two brake plates, with the paint cleaned off with a Scotchbrite wheel and coated with primer:

These bits had their second coat of black on the 31st of July 2026.

FH - running in

 Another sunny day dawns and after more faffing about trying to get the chainsaw to run adequately I went out for some more circuits on the FH. Before I started though, I wanted to check the oil level and top it up - it was virtually full though, so perhaps it had wet sumped since it last ran and emptied the sump back into the tank in the couple of miles I did yesterday.

I also remembered to remove a large magnet I had used to stick a cable clip under the rear mudguard:

The bike ran beautifully, starting easily. The clutch seems a little notchy but the brakes certainly work, though the front is very spongy. There's a lot of flexibility in the lever which we will have to sort out.

It sat here happily burbling away while I took this picture:

On return, I went round the bike with the spanners. After my third circuit, I had noticed the front had started to clonk on braking and I was surprised to find the brake torque arm nut had loosened off.

This brings us to running in. This is what the Ariel instruction book has to say about running in:

It also tells you to change the oil at 1500 miles and decarbonise at 2000 miles. Pitman tells you to change the oil at 200, 500 and 1000 miles.

I'll be checking bolts, chains, cables and brake adjustment very frequently, especially at the beginning, but what of the head gasket? Shall I retorque at some point? I think not, at least not as a matter of priority since it has an annealed solid copper gasket.

The other thing that will be worth checking is the magnetic sump plug, to see if that picks up any nasty debris!

FH - finished!

 Well this is it, I am calling the Huntmaster project finished. In the last post which I wrote yesterday, I fitted the wheels and brakes and tightened up everything in that area.

Today it came off the lift to be replaced by the Square Four and rolled out into the yard for some pictures. 

The yard is halfway up a hill and when I was happy with the pictures I togged up with helmet and gloves and rode it up the road to test the brakes. I've set the tyre pressures to 28 & 36 psi, on the basis that the weight is more or less the same as the SQ4 - though the distribution might be very different - and it's using the same tyres, albeit in different sizes. If nothing else, it's a good starting point.

Several round trips later, each interspersed with some brake adjustment, it was time to take a cup of tea to Mrs H at her allotment. Domestic bliss waits for no man!

Hopefully tomorrow, we will have some time to go a little further.

FH - starting on the brakes

 Now that we are waiting for the tyres and we have the rear mudguard off, we can have a look at the rear brake. For reference, here's the drawing from the parts book:

First glance suggests everything is in order. The springs are all in place and don't look distorted at all; the adjuster is there with the two little mushrooms; there are no cracks in the shoes or the plate.

The shoes look old; they are worn, but not down to the rivets, but they look a bit greasy and glazed. This is the leading shoe:

This is the trailing shoe:

The drum is starting to see wear from being recently wheeled around and used a little:

I'm going to clean these up and see what the engagement looks like using the sandpaper technique. That will let me explore the adjustment and remove any greasy deposits to see if I can improve the performance before I commit to relining the shoes.

I've documented how I do this before, but it's essentially a long strip of 60 grit emery tape stuck to the brake drum with double sided tape. You then back off the adjuster, refit the brake plate and the wheel spindle, and spin the brake plate in the drum.

You then apply the brake with the lever so that the shoes contact the emery. The result is that the linings are reduced in the areas where they are high and this improves the fit of the lining against the drum. In this case, the exercise showed that the linings were already a good fit against the drum, but were clearly rather glazed.

We'll do the same at the front, and test ride it again.

FH - first ride

 Well, a little trip to the workshop today to prepare for a woodwork project resulted in the usual diversion to a motorcycle activity, in this case a bit of time on the Huntmaster. I needed to move everything out to get the table saw ready and that gave me an opportunity to roll the Huntmaster off the bench and out into the yard.

Confirming the starting technique, that of tickling it until fuel flowed onto the drip guard, showed that it starts easily with the choke on - actually first kick. Riding it across the yard shows it engages gear quietly and drives without any horrible sounds. It pulls really well, but the timing side footrest is too far forward and the gear lever is too low.

The brakes are useless. There's far too much lever movement and no bite. They might be covered in grease, they might be glazed, who knows. I will order the rims, spokes and tyres and pull each wheel apart for refurbishment.

Pumping the tyres up shows there's not much height in the centre stand - I've got around 3/8" under the rear tyre.

The side stand is stiff.

It looks great.

FH - another tiny part, and a list...

 A tiny part that takes hours to make mainly because I made it twice to get it right - the linkage from the brake lever to the brake light switch, made from a piece of 1.5 mm thick stainless steel.

So what's next? There's a few things I can think of at the moment:

1. There is a leak from the inlet side rocker box oil banjo, but other than that the engine is finished
2. The primary chaincase has no oil
3. There's a dummy secondary chain fitted, and the end of the FERC is not fitted (and nor are any of the grommets).
4. There's nothing restricting oil flow to the FERC, but apart from that the oil system is finished
5. The dynamo is not proven to charge; the instrument panel wiring needs reworking and the ammeter doesn't stay in it's hole but other than that the electrics are finished
6. The 1/4" screws retaining the clutch dome are either too long or are supposed to be fitted with shakeproof washers. They are actually correct at 3/8" long 1/4" BSW, but it looks like they could have a bit more thread than they have...
7. None of the frame greasing points have been attended to yet, including the one for the new swinging arm bushes. Actually, the two grease nipples for the steering head are missing - not that they will do a lot of good, because the felt washers around the steering column are also missing!
8. The number plate has no numbers
9. The rear section of the rear mudguard is missing a bolt, and the hole it goes through needs enlarging
10. The front brake hasn't been adjusted
11. None of the fasteners have been checked for tightness
12. The wheels and tyres are still untouched

That's it for the moment.

QR50 - assembling the forks

We are approaching assembly time on the QR50 build now, and it will be nice to get it off the bench and to get back onto the Huntmaster. It's been fun and it will be a smart little bike from which I have learned a lot, but I have too many projects at the moment and I want to see the Grandchildren riding this one.

So, while I wait for the gasket set, and for some time to start on the tinware let's assemble the front end. I've used the hone I made to clean the paint out of the yokes, and I use an M8 bolt and a bit of sheet metal to open the clamps a bit, so I can slide the new stanchions in. This is simple, though the balance on the bench is now a bit front-heavy. I hang a big weight on the back.

Looking at my handiwork I notice that the top yoke hits the oil filler - so that was why it was dented on both sides. If you look at this picture, you will see the reason - the steering stop is bent out of the way:

That's easily fixed with an adjustable spanner.

Next, I can assemble the front brake and put the wheel on. It looks great.

QR50 - Brake plate stop

Last major job on the fork sliders is to weld on the stop for the front brake plate. For convenience, I have retrieved this from the old slider:

I've set up the whole assembly in the vice to ensure that it is welded to the new slider in the right place:

With it set up like this I can tack it in place. I can then remove the brake plate, and set the welder up for a fillet; the key element is to make sure I can access the weld:

With sufficient stick out and the gas pressure raised enough to keep the electrode cool, I can use some filler to complete the weld. Any excess is cleaned up with a round file. It fits beautifully:

QR50 - Brake Shoe

Some of the elements of pulling the QR50 out of a pile of bits are specific to the bike, but most of them are very generic. The one that I am going to write about today is the fact that one of the brake shoes had lost it's lining. Now, relining brake shoes is something that I normally entrust to specialists but in this case, which such small loads and relatively little use I am going to try a DIY approach using JB Weld, a metal loaded epoxy with a tensile strength of 5020 psi and able to withstand 550°F.

Now, you can see from this picture that the shoes are rather corroded - if they have anything to do with the forks, they have been outside in the wet for a while:

The first job is to thoroughly clean off all that oxide on the wheel, and get the shoe back to bare metal.

After mixing the JB Weld in equal parts, in accordance with the manufacturers instructions, we spread it on the shoe thinly making sure that the whole area is covered. Then, apply the lining keeping it in the correct position and bind the lining to the shoe with tape.

I removed the tape after 6 hours, and left the shoe for a further 24 hours. I trimmed the edges of the lining and shoe to clean up the hardened squeeze out on the linisher, and the job is done.

Out & about on the CX

I'm happy to say that the 1978 Honda CX500 is out and about again after I sorted out the front brake and replaced the fork oil. It's been off the road for a while after some tyres, refurbishment, camshaft / rev counter investigation and the repair of the broken caliper bleed nipples.

It rides really nicely on its new Avon Roadrider tyres and it positively flies compared to my SQ4 - but it is also very tall and the riding position feels cramped due to the way it makes you bend your ankles.

Cley, North Norfolk

It's got a couple of problems - the tail lights don't work though I have brake lights and indicators, and the starter circuit has a wiring fault. The system demands the clutch is disengaged, even if the bike is in neutral.

Both faults are a feature of this mess:

I've stripped the tape off the harness here - looks like a previous owner let it chafe through and then bodged it together...

More when I fix it.

Dry Build - Fitting the Swinging Arm

Next, it's time to fit the swinging arm and understand how the FERC fits around it.

At first, I struggled to get it in at all. It's difficult because the frame tubes behind the swinging arm mount are more narrow than the width of the swinging arm...

The secret is to lift the frame at the rear, drop the swinging arm and come at it from underneath, with the swinging arm cocked over so the offside is higher than the nearside. Once you get the nearside more or less adjacent to the nearside mount, the offside will rotate up into place. This works because there is more space in front of the offside swing arm mount - the gearbox interrupts the nearside.

I made a decision about the bushes - Steve Carter, marathon FH rider from the AOMCC changed his rubber bushes for a pair of oilite bushes and a much larger swinging arm spindle, and I am going to replicate that approach. Those bushes have a reputation for being a bit of a pig to remove. I thought I would try a hole saw, between the two metal tubes and sawing only through the rubber. It worked fine, with a bit of silicone grease to prevent burning but ultimately my saw was too short:

I resorted to the more traditional approach - a twist drill:

This works very well and of course if sufficiently long will cut all the way along the length of the bush:

The next job of course is to remove the outer sleeves from those 'SilentBloc' bushes. Easier said than done.

My first thought was to weld a plate across the sleeve and drive the whole lot out. I got a decent weld, and then proceed to drift it out - and tore the weld out with the plate attached. The sleeve stayed in the swinging arm.

The Dremel is a more traditional approach and works a treat. I cut a slot in one with a burr; the burr was ruined, but cut one slot before it passed away.

Once you have the slot cut, you can prise the sleeve out of contact and it will be loose enough to drift out.

First battle won.

Dry Build - Rear Brake Pedal & Bell Crank

Updated: first published 15th January 2019

Let's have a look at the brake pedal and crank arrangement next. Here's the crank in place - the rod is very rusty & I broke it trying to dismantle it...

The crank is held in place with a hex head screw (which I think is 5/16" CEI) and a large washer - both of which are missing. There's a clevis on the end of the brake cable.

I'd thought I might buy a new rod assembly from Acme, but having attacked the original with the wire wheel I see that much of it (rod aside) is in pretty good shape and would replate, so I have sat the broken bits in the vice with some Plus-Gas in them.

Drilling that broken rod out is going to be straightforward. Here's how I did it:

I decided to use the lathe to ensure that I drilled the broken std out on-centre. Since it was tricky to hold the banjo shaped swivel in the chuck, I made a simple collet out of a bit of aluminium round bar. The larger part of the swivel would sit behind the collet, which grips the parallel part.

I used the collet to hold the swivel in the 3 jaw chuck, and drilled the bit of broken rod out with progressively larger drills. I cleaned up the thread with a tap.

The rest of it cleaned up easily with the wire wheel. The bolt and washer used to retain the bell crank in the frame are missing - I understand (thanks to Mick D on the AOMCC Forum) that the bolt is 5/16" CEI, about 3/8" long. The thread needs cleaning up:

I've turned up a new washer from a bit of 25 mm 303 round bar:

Moving on, the brake pedal is all good and the spindle fits nicely into it's hole in the frame.

No idea why it is plated though. The spring, although it fits and is working, is very pitted and will need replacement:

I've made a new brake rod from a piece of 1/4" round bar. The collet chuck and tailstock die holder are very useful for jobs like this:

Here we go, new and old:

All fitted up. Next step is a new brake pedal spring and then the brake light switch.

Update:

The brake light switch fits onto a welded bracket on the frame down tube, right above the swinging arm, close to the abutment for the brake cable:

The brake cable uses a clevis arrangement to connect to the bell crank. This one is a bit long, and needs a washer and a split pin: