Rusty metal

While it doesn't look too bad from this angle, the battery tray on this MZ TS125 is falling apart due to acid damage. There is a crack from one of the hooks for the battery retaining strap which means that that tab, with the M5 hole for the side panel is quite floppy.

Since it was only going to cost me a few minutes, I tried to braze it up but in practice it is all too thin to have any strength, so the easiest thing to do is cut it off and make a new one. The bracket used to mount the battery tray on the frame is sound, so we can cut the tray away from it retaining as much as possible of the old tray to provide a pattern for a new one.

I have some 18 SWG cold rolled sheet in the shop, which is a good deal thicker than the original which looks like 22 SWG. You can see the extent of the damage in these pictures.

The new one is very simply folded from sheet, cut out with the jigsaw & hacksaw and with 5 mm holes drilled into the corners for clearance and drainage. We'll tack the corners together with the MIG welder.

Here's the hooks folded down and around the old strap.

So now I have transferred the side panel tab to the new tray, and brazed it in place in case I have to move it again. Next, to weld up the corners and finally weld the tray back to the frame:

Welding the outsite of corners is tricky if you are not to blow the material away completely; my welding needs a lot of dressing! Corners done, we'll tack it in place using the old one as a guide:

We'll need to fit some other parts around it to confirm that the side panel mount is in the correct location, and then we will complete those welds underneath. Removing it with those fully welded would probably destroy my new tray.

Just a little U-Pol etch primer to avoid rusting...

A few days later I have the cast aluminium rear mudguard and the coil bracket to mount up and test my new battery bracket. I'll put the lot in the vice and mount the rear end with some 10 mm pins, that are a close fit in the holes and don't allow any wobble:

You can see the three M6 mounting holes for the side panel - one in my battery bracket, one on the coil bracket and one in the mudguard. Here's the side panel mounted up:

Perfect! now we can weld up and apply some paint.

And that's it, ready to be returned to its owner.

Huntmaster - the next steps

Hopefully the next month will see a bit of space appear in the garage when the MZ TS250/1 departs for a new life. When that happens, we will be able to crack into the Huntmaster. This is the general plan:

1. Complete the dry rebuild of the forks & nacelle, leaving cleaning up the oil seal holders until strip down;
2. Get the mudguards, seat base and chain guards grit blasted ready for welding;
3. Build up the frame and swinging arm, dry fit engine plates, gearbox, seat, swinging arm, mudguard etc.;
4. Repair the seat base, chain guards and mudguard while the frame is on the bench & available for test fitting;
5. Strip it all down and prepare for painting;
6. Send the black parts to the Horsford powder coater;
7. Send the tanks and toolbox to Ian Potter;
8. Strip and rebuild the gearbox & clutch;
9. Strip the engine, inspect and send the bottom end to SRM, including the original cases;
10. Recondition the dynamo;
11. Send the magneto for refurbishment;
12. Clean the wheels and fit new Avon tyres;

We can work on the rebuild process later - that is quite enough to be going on with! Feel free to comment.

The only fly in the ointment? This:

Another TS125, whose frame is already in my workshop for a battery tray repair...

Special tools

Special tools, those that are devised to make some unusual job that bit easier, come in all shapes and sizes.  Having no desire to pull the Square Four forks apart again (since I have the Huntmaster ones to do) I decided to see if the recalcitrant forks bushes would free themselves with a little brute force, tempered with at least a little intellect.

I thought I would be able to pull the stanchions out of the fork sliders without taking the forks apart again, by persuading the bottom yoke away from the wheel, thus pulling the stanchions away from the sliders.

The front mudguard is a serious piece of engineering (especially with all the welding wire I added to it) and it can take a bit of force. I devised a tool made from a block of 3/4" ply to spread a load into the mudguard:

Five minutes with a stout bit of bar saw the fork stanchions pop out of the sliders. Hopefully the next time I hit that pot hole the forks will have worn a little and won't get stuck again.

State of our Roads

There are some outrageous pot holes around here. There's one I always forget about on a hill nearby, which has been filled in but is now sunken again making a smooth but significant hole.

So sunken in fact that Amelia's forks haven't recovered yet:

I think we have a fork bush clearance problem!

Ariel Side Stand

I've noticed a couple of times lately that my Square Four side stand spring has become detached from the stand, leaving the stand swinging in the breeze and ready to throw me off on the next left hander. This is the 2450-48 & 2450-50 short side stand fitted to 1948-52 bikes.

I've retained the spring with a tie wrap. Hopefully this will sort it out. The stand is still free to move, but the location of the spring is now controlled so that the spring cannot pop out from under the stud.

It's an awful side stand - I rarely use it.

Steering Lock

As part of the fork rebuild, I bought a steering lock for the Huntmaster from Draganfly. It fits in this forged lug on the bottom yoke, and it was obviously not originally fitted - the lug was full of maroon paint. It pushes in from underneath and is retained by a grub screw:

Here's the frame lug that the steering lock pin will fit into one day:

This next shot, which comes from someone on the AOMCC forum, shows the frame lug for the steering lock pin with the yokes in place. I guess that thin sheet over the top is to prevent the potential thief removing the lock by punching it out from above:

Another New Tank

Regular readers may remember the stripy blue tank I bought last year, which I had blasted. Following the blasting it became obvious that it was going to need a lot of welding...

I decided to scout around for another and came up with this:

It's a very solid tank and it is in first paint. I fitted a new tap and the crossover pipe from the rusty tank. It's sitting here with 20 litres of acetic acid in it, to descale the inside for a week. The plan is to fit in in this form and run it over the summer, to see how it goes - I have to pull the tank off to attend to the head bolts, the tappets and to move the distributor.

Temperature Testing

So, I've planned out a series of temperature tests, to examine the temperatures at which various parts of the engine are running.

The objective is to discover whether all the cylinders are running at consistent temperatures or whether there is evidence of higher temperatures on one or two cylinders, which might indicate excessive friction.

I'm using an infra-red thermometer to measure the temperatures. It has a measurement range of between -50°C and 550°C (between -58°F and 1022°F); you just pull the trigger, it lights the laser to enable you to aim the unit and it will display the temperature on the back. The display illuminates at the same time, and it will hold the value display while you pull the trigger.

The results sheet show details of each test and of the results. I have shown some calculations as I want to record the temperature differences between the cylinders.

Many folk have written about how these engines will see 250-350°F at the top end. Mark Walsh's experience steadies my nerves:

This is pretty much what my own Four is doing at the moment, with considerably less miles on the clock.

Huntmaster Forks & Nacelle

So, having cleared some space in the workshop after sorting out the Square Four fork bushes, and having the fork tools out and the assembly details still loaded into my mind, I thought I would check out the nacelle and get an understanding of how it fits, what parts were missing and what parts were broken.

So here is the top view, with the nacelle and the instrument panel in place. All the fasteners are, surprisingly enough, missing - those hexagonal plugs are incorrect for that location I think. The stem nut and its washer are missing, as are the screws for the instrument panel. The instrument panel is a little bent, and may be cracked - there is a lot of braze around the handlebar clamp. In reality this is scarcely visible and will be easily remedied.

Under the instrument panel, everything looks good. I'm not sure whether the headlamp shell is supposed to be fitted grommet 'up' or with the cables exiting downwards...

Something else I did not expect - rear fixing holes. The nacelle is also a little distorted around the bottom yoke - easily fixed. The correct MCH60 headlamp shell is here - I am lucky to have that. The steering lock is missing, but the grub screw is in place and the damper is all together apart from that top nut.

I have the small bridge piece under the nacelle, no fasteners and the holes are a little worn - nothing that will be visible in service. The headlamp shell has lost one of its captive nut cages, though the nut is there. The alloy trim, which fits in those holes on top of the nacelle, is also missing.

Here's the headlamp, with the shell refitted grommet down. Thanks to the guys on the AOMCC Forum, I now know that this isn't the correct way, but it is the only way you can get access to the rim clamp.

Here's one of those top fork nuts. I'm not sure what it is - it's been shortened by someone.

Here's the fork top plug, which fits under the top bolt. Not sure why they needed both, but both of these are in place.

So all in all, not too bad. I have ordered the missing parts from Draganfly; next stop is to strip the legs and see what the bushes look like. The chrome shrouds have been painted, possibly using an etching primer - it looks like the chrome is coming off.

A braze repair makes short work of a crack in the instrument panel, smoothed with a good dose of flap-wheel:

And a little filing has the slots fitting neatly around the handlebar clamp studs:

Originality or Taste?

I think I have decided that I am going to veer away from originality on my Huntmaster paintwork.

These are the options:

Late FH in original, domestic-market maroon

The maroon bike shown above is how my bike would have appeared when new. The frame has been refinished in this colour, as have the oil tank and tool box; the shrouds, nacelle, fork legs, tank and mudguards are black, though very poorly painted. this picture comes from Classicandracebike.co.uk, so thanks to them for the picture.

This is the option, the glamorous red and black export market paintwork available in the US market - quite why Ariel's marketing group, if they had one, thought the domestic market would want the rather dour yet traditional maroon rather than this racy red is beyond me. This bike isn't a Cyclone, so its performance is just the same as the maroon one, but it looks like it's a lot faster to me.

Late model FH in original export-market red and black

This picture comes from the US Ariel Club, at www.arielnorthamerica.org our sister club. Here's a nice looking VH in that paint, from Andy Tiernan's shop:

The troubling thing? My bike's original buff log book states 'maroon'; it's a matching numbers bike and it seems a shame to change any of those details - but it's my bike and there are a lot of maroon Huntmasters out there.

Contrary to my usual all-original approach, my current thinking is that I am going for the export paintwork for this bike.

Sunday Jaunt

So the sun and a spare hour appeared and with the Ariel ready and waiting it was time for a little jaunt into the Norfolk countryside. Late on a Sunday afternoon, with school and work the next day, the roads are pretty empty up here and the worst thing you have to contend with is the sun low in the sky when you are heading east.

We rode out from Sheringham along the coast road to the village of Weybourne, and avoiding the spectacular NNR for the moment we rode up and over Kelling Heath to Holt, coming back along the main road to Bodham. Over the bumps, the Ariel is realizing the benefits of new fork bushes - the front end feels more secure and is considerably less noisy.

She's also loosening up nicely, and opening up from the 30 mph restrictions through High Kelling onto the open road, she feels smooth and powerful. We turned at Bodham and stopped for a picture at Kelling Heath again, by a pill box.

We then tested the new brakes down the steep hill to Weybourne station, and posed for The Bridge Club.

Dropping further down the hill, it was time to open her up again for the short run into Weybourne village and back home to Sheringham.

15 miles run, finishing with about 25 psi on the oil pressure gauge. Lovely.

Fork Bushes

Due to my phased approach to building my SQ4, I put the forks back together without re-bushing them, many moons ago. They weren't too bad at the time and since Amelia had arrived in a number of boxes, and I had no Ariel experience at the time, I needed to get it assembled to understand what I was dealing with.

Dashing about Norfolk's roads last year showed re-bushing was going to be necessary this winter, so off we go.

The first step was to truss her up with a bungee to stop her shaking her head about. I planned to leave the yokes in place to avoid unnecessary disruption to a running bike.

Then, we need to get the front wheel off the ground without the ever-useful front stand. A scissor jack comes into play here:

Next step is to remove the front wheel, mudguard stays on one side and remove the fork top bolt and clamping cap screw in the bottom yoke. Next, we use the fork puller tool to knock the stanchion out of the taper in the top yoke:

With the leg out, we can start disassembling. We put the leg in the vice using the cast lug on the bottom - we don't want to clamp around the thin slider. Having lifted off the spring, we can use the special tool to remove the seal holder.

With the seal holder undone, we can think about the next step. Lift the seal holder about six inches up the fork leg, and tape it out of the way. Don't try and pull it off upwards, as the leg is tapered and you will stretch the seal.

The top bush retains the leg in the slider, since the bottom bush is bolted to the leg, and the top bush is retained by a circlip under the seal. Here's the circlip in place:

You can see, at just past 12 o'clock, a semicircular groove. This gives you access to the full diameter of the circlip. Get a small flat bladed screwdriver into the groove and push the circlip out. Find the end of the circlip and maneuver the screwdriver, still holding the circlip clear of the groove, towards the end of the circlip. When the end of the circlip is free of its groove, get a scriber or another small screwdriver under the end of the circlip and maneuver it upwards, moving back along the circlip as you winkle it out.

You can then pull the leg out of the slider:

These two pairs oil holes ( the others are behind the leg) show this is a post 1953 leg, which gives more progressive rebound damping than the earlier legs (which only have one pair of holes). The long top bushes which go with these later legs are shown in the picture above; earlier legs use a top bush of about half this length.

Here are the new bushes in place.They were both oversize on the outside diameter and required some 'easing'; The lower bush is retained by the stanchion bottom nut.

The next job is to lubricate the buses with some SAE 30 and place the stanchion back in the slider. You can then maneuver the circlip back into place by aligning one end in it's groove, and pushing the clip away from the retained end with a small screwdriver until it snaps into place. Next, put a little more oil around the top bush and screw the seal holder back down with the factory tool; fit the spring and you are done:

This is a new H18-48 stanchion top adapter, courtesy of Mr. John Budgen. The previous one succumbed to an unfortunate incident involving a copper mallet and a lack of forethought. You can see how it used to look in the previous picture - they are not very strong and cannot tolerate much abuse.

Once you have it all back together, you will need to fill the forks up with some SAE 30 engine oil. This is simply accomplished by removing the top bolt and, with a small funnel, pouring sufficient oil into the leg such that the level is 17-18 inches (43 cm) from the top of the yoke.

For reference, here is a sectioned drawing of the fork from Mr Charles Weller's book.