Wednesday, 7 September 2022

WELCOME to my blog about restoring vintage overhead camshaft AJS motorcycles


.....although a few other projects creep in from time to time.

It's a few weeks since I last posted on my blog. There has been reasonable progress on the AJS 33/7 Trophy project but I have also spent time fettling my Velocette Thruxton and the AJS R10 to take to the 2022 Manx GP in the Isle of Man.

This is the Velo with Peel harbour in the background:

and this is the R10 at The Goosneck:

There is more about the more recent work on the AJS 33/7 and the IoM trip here.

During the last couple of years I have posted quite a lot of information and to aid navigation the "Labels" section on the right side of this page list the various projects.

The labels marked "INDEX" give a link to a page that provides a complete list and links to all of the separate sub-projects related to that main project.

Alternatively, scroll down this page and see what's here...

When I started this blog I already owned (and still own) a 500cc AJS R10

that I've been riding for many years and wanted an early 350cc bike. I bought one at a Bonhams auction; this is what I brought home....

....a bit of work was needed to bring it to back to life 

Full details of the restoration can be found here.

During the restoration of the K7 I figured that I could put an early overhead camshaft Velocette cylinder, cylinder head and cambox onto the crankcases of an AJS 350cc engine from 1931, convert it to chain-driven OHC and make an engine that looks like a K7 but has a Velocette top-end. I had a 1928 350cc AJS sidevalve that I had bought on eBay and used that to create the AJcette credit to both manufacturers.

It looks pretty similar to the K7 and to demonstrate that there really are 2 bikes, here they are both together.

Details of the AJcette project can be found here.

I have quite a lot of early Mk1 OHC Velocette parts and after completing the AJcette I decided to try and make a replica of a one-off bike that AJS built in 1929/1930 for an attempt on the world speed record. The original is a huge V-Twin beast that started out with a naturally-aspirated engine but, having failed to gain the record, was supercharged ...and again failed. The bike ended up in Tasmania for many years and, after being repatriated to the UK and restored, it is now in the National Motorcycle Museum.

This is what the original looked like:

and this is my recreation.



Like the AJcette, the V-Twin uses Mk 1 OHC Velocette cylinder components. The full story of how this bike was built can be found in the links here.

There is also a 14 minute edited Youtube summary of how these bikes came about here and a longer unedited version here.

....and so to the current project. I have started (January 2022) the restoration of a 1933 AJS Trophy Model.

The Index Page for this ongoing project can be found here and I'll add more  as the project evolves.

I also reported on a couple of my other projects ....vintage OHV Nortons

 and putting a Marshall supercharger onto my 1934 MG PA


I hope you find something of interest.

The AJS 33/7 Trophy Model Restoration, a day with Ron Langston and the 2022 Manx GP:

I haven’t posted anything on my blog since the end of July but that doesn’t mean nothing has been happening. In fact, quite the opposite.

First, an update on the current AJS 33/7 restoration project.


I had already bought the mudguards from Renovation Spares – 4 ½” D-section for the rear and 4” for the front but the stays needed repairing/making.

Up to now, I have machined the “ends” for the mudguard stays, inserted these into ½” OD steel tubing and silver soldered them in place. I decided that it was time to make a press tool to enable properly flared ends to be made. The tool for this is shown below together with an “end” after pressing.

The 2x ¼” diameter pins hold the 2 top and bottom of the press tool in place and the initial pressing is done in the vice.

Although I have a decent sized vice I cannot exert sufficient pressure to get a completely flat end and the 20 ton press is used to complete the task. I have found it needs about 6 tons.

The end result, after drilling and radiusing the end looks OK.

The rear mudguard stay was repaired

and new brackets made by bending a flat steel bar over an appropriately sized former.

Similarly, new brackets and stays were made for the front mudguard.

The front mudguard has yet to be trimmed to length and the front wheel stand made.

Petrol Tank

I wrote quite a bit about the repair to the petrol tank in my last blog post but two tasks remained: firstly, a proper panel was needed for the top of the tank rather than the crude piece of sheet metal that had been cut out of a Castrol sign and, secondly, attachments to hold the side rubbers need to be fabricated. Although the bike will be fitted with lights, I don’t plan to have the switches in the tank panel but rather in the headlight and therefore only a simple plane panel is needed. However the panel does need a swaged edge for the correct appearance and to otherwise avoid cutting fingers on the edge of a piece of sheet steel.

The first step was to capture the shape of the panel by smearing grease on the contact surface and then transferring that, including the locations of the 3 holes onto a piece of cardboard (I’m still using up pieces of cardboard from returned laundered shirts from my days in staying in hotels on business trips during my working life – I retired nearly 7 years ago and still have plenty of pieces of cardboard left) .

The line around the outside of the grease has been added to give an allowance for the swage. The cardboard was then cut around the outline and the shape transferred to a piece of 18 gauge steel sheet, cut out with a disk cutter and finished with a finger sander.

The edge was then swaged in the edge roller

to produce a panel that fits the tank exactly and with a proper edge.

In due course, the panel will be sprayed gloss black whilst the remainder of the tank will be chrome plated.


Although I had a kickstart that was a good fit on the splines it was not a folding kickstart. I suspect that a non-folding kickstart would have been fitted originally but, as I always end up catching my leg, often painfully, on non-folding kickstarts I decided in the interests of enjoyment to modify the kickstart into one of the folding variety.

As with the V-Twin, I bought a Triumph folding kickstart off ebay for a few pounds, chopped it in 2 and welded the top part onto the Sturmey Archer bottom splined part. The picture below shows the new modified one on the left and the remaining bits on the right.

A day with Ron Langston

I have got to know Ron very well over recent years having ridden with him in a number of Ariel rallies in Italy (although I have ridden either a Velocette or a Norton but never actually taken an Ariel) and Ron has taken a keen interest in the build of the AJS V-Twin. Anyway, Ron invited us to bring the V-Twin to his open day which was held at his house back in July and the event is very well described here.

For me, one of the most interesting bikes on show was the Velocette Roarer, which I have never seen running before. This brief video clip shows the Roarer being run by Graham Rhodes ably assisted by Ivan.

Graham, incidentally, is a past winner at the Newcomers Senior Classic race at the Manx GP on a Seeley 500, a race that I watched from Creg-Na-Baa back in 2005.

The 2022 Manx GP

There would have been more progress on the cammy AJS restoration if I hadn’t needed to do some preparatory work, and then of course go to, the 2022 Manx GP. I have been going to the Isle of Man for either the TT or the Manx GP since 1978 – the year that Mike Hailwood made his comeback on a Ducati. I missed a few years when we lived abroad in Austria and bringing up our family but I’ve been taking older bikes for at least the last 20 years. This is a picture from the 2010 MGP with the R10 in the foreground and my mates Velo behind – and I’m sandwiched in between.

For those that know the IoM, this picture is taken at the crossroads where the roads from Foxdale and Glen Maye intersect. The resolution is poor because it was taken on a phone camera of that era.

And so to this year….. The 2020 and 2021 MGP events did not happen because of covid and I, together with many others, had our ferry booking “bounced” into 2022.

I had decided to take the recommissioned Velocette Thruxton and the AJS R10. However, as I reported in a previous blog  I had fitted a new cylinder barrel and piston on the Velo and I needed to get some running-in miles before using the bike  in the IoM. The first run out to a local petrol station did not go well: I could not start the bike after filling the tank. It did start OK by pushing it up a hill and then bump starting it but having to do that does take the pleasure out of a ride. As the bike had been standing for some time and poor hot starting is often attributed to weakness in the magneto I decided that Paul at APL really need to take a look at the mag and do whatever was necessary.

This resulted in a near complete rebuild – rewound armature, new slip ring, bearings etc..

The Velo is also now fitted with the correct 1 3/8” T5GP2 carburettor and as these instruments were developed for the racing engines of the day the focus was on high speed performance rather than ease of starting. Difficult starting can arise because the large diameter (and hence large cross-sectional area) produces a correspondingly lower air velocity at the choke and this, in turn, produces a smaller pressure drop (below atmospheric pressure) to entrain fuel and so getting a good fuel/air mixture into the cylinder is problematical.

Easier starting can often be achieved by using the tickler. For any reader that is not familiar with older carburetted engines, the “tickler” is a small spring-loaded plunger on the top of the float chamber to press down on the float to provide excess fuel for starting. However, the tickler on the matchbox float chamber used here on the GP carburettor, is completely inaccessible with a finger because it is hidden behind the toolbox, but it can be depressed with a short, flat wooden stick – a “tickling stick” (for those in the UK, this is nothing to do with Ken Dodd). It is also necessary to position the kickstart using the “Velocette Starting Technique” (Google will explain what that is) and I can nearly claim first kick starting. Not bad for a high compression engine with a large racing carburettor.

Anyway, the Velo, pictured here with a backdrop of Peel Harbour at The Creek Inn

and the R10 holding up the bank at The Gooseneck

performed faultlessly for my 10 days in the Isle of Man.

For various reasons, the 2022 Manx GP was probably the last time I will visit the IoM so it’s good to go out on a “high”.

Wednesday, 20 July 2022

The AJS 33/7 Trophy Model Restoration: The Petrol Tank, Battery Carrier, Oil Pipes, Gear Lever, Footrests, Carburettor and Wheels

It’s been over a month since my last blog post about the gearchange positive stop. Quite a lot has happened during the past weeks and various longer term sub-projects have come to fruition. I have also spent an unbelievable amount of time on bureaucracy - with which I am not accustomed, sorting out various UK government related issues for our Ukrainian mother and daughter that now reside with us – see previous posting.

But now, back to motorbikes!

The Petrol Tank

The petrol tank that came with the bike is the original tank that would have been made by AJS in 1933. This is a picture of it on the bike before restoration was started.

The tank still has its original chrome plating and I plan to have it re-chromed, BUT there are 2 large dents that spoil the appearance. If the tank was to be painted then this would not be a problem (because the dents could be filled) but chroming requires a very smooth surface finish of the original steel …and free of dents! The 2 pictures below show the damage to the left and right side front surfaces.

The first step was to send the tank to a local plating company to have the existing chrome plating stripped back to bare metal.

As regular readers of my blog will know, I try and do as much as possible in my own workshop but, as I’ve mentioned on a number of previous occasions, I have neither the specialist skills nor equipment to take on complex sheet metalwork projects. One of the difficulties that all restorers have these days is finding craftsmen with the skills required to be able to repair damage such as this. The re-purposed Royal Enfield Bullet tool box into an oiltank for the V-Twin is at the limit of my expertise.

Luckily, I have a good buddy whose brother-in-law has spent his whole life doing complicated things in sheet metal and with some gentle persuasion he took on the job of taking out the dents in my tank. This was not a 5 minute job! The first step was to carefully remove the weld at the seam and peel back the bottom of the tank to gain access to the inside.

Incidentally, the rusty appearance is merely surface rust and the sheet metal is actually in very good condition. The surface rust will disappear in processes to be applied later.

With access to the inside of the tank the dents were very carefully beaten out to give a completely smooth surface for plating.

The bottom of the tank was then reattached with the TIG welder and tested for leaks - I pour in a couple of pints of cellulose thinners because it will find every leak there is and it doesn’t leave a residue. One of the welded-on lugs was found to leak (the one in the bottom right corner in the picture below). This is a common problem with this design of tank fixing because people use a bolt that is too long ….and simply keep winding it through the thread until it goes through the tank. The entire lug was removed carefully with a dremel, the hole repaired and the lug reattached. Again, not a 5 minute job.

I now have a tank that is dent-free, with a surface suitable for chrome plating and holds fuel without leaking. Thank you Jo!

Oil Pipes, Gear/Brake Levers and Footrests

Making the oil pipes has followed the same practice as previous projects, namely bending pieces of fence wire into the required length and shape (as the Kiwis would say, use number 8 wire) and then anneal and bend the pipe accordingly before silver soldering a banjo connector or nipple onto the ends.

Nowhere near as many pipes as the V-Twin! In the last picture, the gear lever shown has been made from a section of 30mm x 10mm steel. The main taper of 0.80 was machined on the milling machine and the lever was silver soldered onto a spare splined section that had previously been used for an external linkage on some racing bike (that’s the brazed bit). Filling the centre hole and a peg for the rubber are yet to be done.

The serrated end of the extension for the footrest can also be seen; there is a similar piece on the other side of the bike. Although simple looking pieces, there is quite a lot of work in making these. The serration requires careful setup on the milling machine with a rotary indexer and a 450 angle plate and the 7/16” square hole in the centre (to fit the 7/16” square bar that passes through the engine plates) is spark eroded.

On the left side of the bike, the brake pedal has been made to replicate an original.

And the battery carrier has been remade in its entirety. The long securing bolt on the top has both LH and RH threads.

The Carburettor

The AJS 33/7 Trophy has an Amal Type 6 carburettor and because of its downdraught fitting has a 150 angled float chamber. Luckily, and although the external appearance changed, Amal did not change much inside the carburettor as it evolved in later years into the Types 76 and 276 and most of the internals are interchangeable – see here. The external appearance of the float chamber is also different between the early and later models. These earlier carbs and float chambers are much rarer than the later models and difficult to find if they are missing.

The carb itelf showed minimal wear and it was sufficient to renew the internals - jets, needle, main slide, adjusters etc with new parts, shown below.

The Wheels

Last, but by no means least, the newly built wheels came back from Wheelwise. As always, Steve has made a perfect job of these.

And, with new 20” tyres and tubes from Vintage Tyres and new (soft) brake linings and springs I now have something that is starting to resemble a motorbike.