Friday 23 December 2022

The AJS 33/7 Trophy Model Restoration: Metal Finishing ….and a Trip to Ukraine

At this stage the dry build was essentially complete and ready for stripping back to the last nut and bolt. It takes considerably less time to take the bike apart than to build it: It took around 11 months to build it and 2 days to strip it!

In the picture above, the parts have been separated into 4 boxes. From right to left these are: parts for powder coating, parts requiring other finishing (chemical blacking, zinc chromate plating or 2-pack paint for the oil tank), chrome plating and parts requiring no further work. The parts for chroming were delivered to Castle Chrome  and to Autoblast for powder coating. I have only had good experience with both of the companies.

As with previous projects, I plate the smaller components myself. The plating bath was set up

for the zinc plating and this bubbles away for a couple of weeks depositing a thin layer of zinc on all the smaller components – oil pipes, nut, bolts etc. When plating has finished, each component is dipped into another bucket of liquid for a few seconds and this converts the zinc to a complex mixture of chromium compounds. When polished, the surface is a pretty good approximation to chrome plating. The picture below shows 3 oil pipes that have been plated; the 2 outer pipes show the dull appearance after plating but before polishing whilst the pipe in the centre has been polished.

....and after a few days of the bubbling plating bath:

 Another small job was engraving the positive-stop gear change
indicator outer plate.

With most of the parts sent out for either plating or powder coating it was time to turn attention to another project.


Generators to Ukraine

Those that have read my previous blogs would know that we had a Ukrainian mother and her young daughter staying with us under the UK government’s Homes for Ukraine scheme. I posted this picture some time ago of Tanya, who lives in Kyiv during less troubled times, astride the V-Twin.

Tanya came to us shortly after the start of the war when the Russian army was marching on Kyiv and stayed with us until the end of October when she decided to go back to be with her family. Shortly after she returned the missile and drone attacks on Ukraine’s infrastructure started. We had kept in contact and when I asked if she was OK she said “yes, we’re fine, we have power for 2 – 3 hours a day”. That is not exactly my idea of “fine” and so I decided to try and help in a small way by providing small generators to help the people of Ukraine, the plan being to purchase petrol generators in the UK and to drive these out to Ukraine in my old Ford Transit.

I started a crowdfunding page  to help with the finance and simultaneously starting buying generators from various suppliers. It was fortuitous that I started buying generators at the outset as I found later that stocks from many suppliers ran out and prices increased considerably.

I ended up with 16 new generators of various powers (2.2kW to 6.5kW), specifically:

6 of these:

4 of these:

2 of these:

and the 4 largest Excel generators (2x 4kW and 2x 6.5kW):

I also found 2 new generators on ebay at a good price and a kind local lady donated another, making a total of 19.

After an overnight car ferry to France and then a 3 day drive through snow-covered Europe I ended up in Lviv. We unloaded the generators at the Catholic University of Lviv (a repository for humanitarian aid)

and the van was donated to the Ukrainian military

In the above picture, Tanya and I are sandwiched between the 2 guys from the military that took away the van.

The generators will be taken to the East of Ukraine, an area that has suffered some of the most damage to the electricity infrastructure and the van, which has a load capacity of 1900kg, will go to the Donbas, around 100 miles back from the front lines, for transporting supplies. I flew back to the UK from Krakow airport.

Putin: Give up now! You don’t stand a chance against a Mk 5 Transit.


Saturday 19 November 2022

The AJS 33/7 Trophy Model Restoration: The Cylinder Head Steady

I haven’t posted anything on the restoration for about 6 weeks, mainly because the dry build is nearly complete and there have been many little “tidying up” jobs that are not really worth reporting. One sub-project that has come to fruition is remaking the cylinder head steady. This is essentially a clamp on the front frame downtube that is attached with a 5/16” bolt and eye to the cylinder head.

This is what it should look like (picture from my R10):

And this is the clamp that came with the bike:

Someone has made an effort to make this clamp but, whilst I am not a stickler for total originality, this clamp is pretty ugly and would not be out of place supporting a car exhaust system.

I decided to make new clamps using the originals on my R10 as patterns. The process for the castings follows identically that used for the exhaust rings on the V-Twin and other small components that I’ve made in the past.

The starting point is take one of the clamps (it doesn’t matter which one is used – they are both the same):

and to build a small wooden box with 2BA screws around the clamp.

Short lengths of 5/16” diameter aluminium are then attached to the top of the clamp to act as a feed sprue and riser and the arrangement is then suspended about 1cm above the bottom of the box. The 2 pieces of brazing rod are to keep it level. The sides and bottom of the box and the screw threads are coated with Vaseline.

RTV silicone rubber is then mixed and poured up to the top of the part

and after setting, the RTV silicone surface is coated with Vaseline and more RTV added up to the bottom of the screw heads.

The mould can now be dismantled to remove the original clamp.

After reassembly and with the addition of a paper funnel for pouring, resin can now be poured into the mould

and, after hardening, a facsimile of the original component in resin can be removed. 2 were made and sent off to the foundry.

I used a local foundry, White Eagle, who cast these in “Naval Bronze”. Bronze is really a misnomer for this alloy as it consists of copper and zinc – which should really be referred to as brass. Anyway, this is more than adequate for these clamps. After a short time, I picked up 4 newly-cast clamps.

and, after some machining, these were ready for fitting.

There is one deficiency in the original AJS design: the threaded end of the connecting piece cannot be inserted into the cylinder head when the head is assembled on the bike – there is simply insufficient space to avoid the front frame downtube. The picture below is from the R10.

I therefore made the connecting piece as a turnbuckle – a RH thread in the cylinder head and a LH thread into a separate connecting eye.

The advantage of this design is that it can be positioned accurately and attached with the cylinder head in place.

There are many smaller jobs on which I haven’t yet reported but the dry build is essentially complete and the bike will shortly be stripped back to every component for painting and plating. I have also not yet stripped either the bottom-end of the engine or the front forks so we’ll see what surprises they yield.

Wednesday 12 October 2022

The AJS 33/7 Trophy Model Restoration: Headlight Bracket, Front Stand and Seat

Quite a few cycle parts were absent on the bike “as received” – it had been “flat-tracked” and there’s not much need for a headlight or a front stand if you’re racing.

Headlight Brackets

I had already decided that I would use a headlight with an integral switch rather than having the switch in the tank panel and I bought most of the electrical system – the headlight, rear light, battery (a lead-acid gel unit) and dummy battery container etc from Paul Goff. However, there was no bracketry for the headlight. Luckily, Bonhams post high-res pictures of the bikes that they sell and leave them for all to see after the auction (if anyone from Bonhams ever reads my blog, then "Thank You" ....and please keep posting the detailed pictures - they are incredibly useful to restorers) and a pretty original barn find34/10 (the 1934 500cc model) was sold at the 2010 Spring Stafford sale. A couple of the pictures on Bonhams website show the headlight and bracketry in sufficient detail and helped me fabricate a replacement.

Picture courtesy of Bonhams

As I’m using a switched headlight I needed a little more space to move the headlight forward a bit and so a swan-neck lower part of the bracket was made

but, overall, it’s a pretty fair copy of the original

 Front Stand

Up to this point, I still hadn’t finished the front mudguard fixings; in common with many bikes of the period the lower mudguard stay is a front wheel stand. Again, a picture of the same barn-find AJS 34/10 shows the detail.

Picture courtesy of Bonhams

By scaling against the fork tubes, I estimated the diameter of the tubing used for the stand to be ~ 0.625”. Unfortunately, the maximum diameter that I can accommodate in my pipe bender is ½” and I also cannot bend the tight radius that is required. Luckily, there are plenty of these stands around and it didn’t take long to find one that could be modified to fit – it came from my buddy JT and so it was probably originally fitted to an Ariel.

After cutting:

and shutting:

it fits the AJS perfectly.

Repairing the Seat

The Dunlop seat that was fitted to the bike was in poor condition. Whilst I appreciate patina, the rubber of the original covering was so hard that it would have probably disintegrated the first ride out.

but is period correct, as seen in the 1931 Dunlop brochure.

Picture courtesy of Velobanjogent

Luckily, high quality reproduction rubber covers are being made and so I decided to refurbish the seat myself. The 3 main metal parts of the seat were grit blasted and then painted

split copper rivets of the correct size were obtained and annealed (The "as received" copper rivets were work-hardened from the manufacturing process and not easily splayed. Annealing them - red hot with oxy-acetylene and throwing into cold water restores them to a soft malleable condition)

and the rubber cover carefully drilled and re-riveted.  

The “Dunlop” plate was removed from the old cover and affixed to the new one.


With the front mudguard and headlight fittings completed, the refurbished Dunlop saddle and the exhaust temporarily fitted prior to making the brackets the bike is starting to look like a proper 1930s off-roader.