WELCOME to my blog about restoring vintage overhead camshaft AJS and Velocette motorcycles

 Apologies to anyone that has come to this page expecting to see exclusively vintage AJS motorcycles .....scroll down the page a bit and you will find plenty of them.

However, I sent all of my cammy AJSs to Bonhams last year and they were sold at the Autumn Stafford Sale. 

The URL of "vintageajs" for this blog is now somewhat misleading but it's too late to change it and there is still plenty to read about the AJAY projects. If you happen to be the new owner of one of the bikes that I recently sold then there is plenty here to read about its build. I still have 2 early Big Ports waiting in the wings ....but they will have to wait until I've completed the Velos. 

In 2023 I started the restoration of 2 early Velocette KTTs plus another Mk 1 OHC cammy special - a few details about each of these bikes can be found here and here. 

A lot of work has been done on these bikes over the past 3 years and the INDEX PAGE provides links in chronological order of these projects so far.

In August 2025 I acquired a DOHC 250 Velo Engine and decided to use a spare Mk 1 chassis to house that rather than the early Model K engine that I had originally planned to use. I have rebuilt this engine and the final build of the bike is also now finished. Details of this project can be found in the links in this INDEX page.

I also acquired the engine, exhaust pipe and petrol tank of KTT 581 early last year. This bike has an interesting and somewhat sad history. I have rebuilt the engine and plan to put this in a bike when I have completed the current 3 Velos - full details of this project so far in the links Here.

The Final Builds of both KTTs and the DOHC 250 are now complete

and it's time to fire them up for the first time.

Some details of the final build of KTT 55

and it's first start can be found HERE.

During the last 5 years I have posted quite a lot of information and to aid navigation the "Labels" section on the right side of this page lists 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 owned 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 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 ....giving 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 use some of these to 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. 

This bike is now in the Sammy Miller Museum.

 

In January 2022 I started the restoration of a 1933 AJS Trophy Model

and this was completed in March 2023.

 

The Index Page for this project can be found here.

I also reported briefly 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.

Final Build and First Start of KTT 55

Apologies if my blog is starting to look somewhat repetitious but it’s difficult to avoid a certain amount of repetition when building 3 very similar bikes simultaneously.

This was the last one, KTT 55, that I have just completed

and this is the trio of (from rear to front) KTT 305, the DOHC 250 and KTT 55 assembled in the back garden for the first time.

The procedure for the last one has followed exactly the same format as the previous builds, namely strip the dry-build bike, sort into boxes for “no further work required”, “plating”, “chemical blacking”, “powder coating” and “painting”. When building this 3^rd bike the phrase “…same procedure as last year” came to mind. If you live in continental Europe this will probably mean something to you; if not, check out this link for an explanation and this link for the movie.

There were not many parts for plating

or chemical blacking

but, as with the other bikes, the petrol tank takes by far the most time and effort.

After stripping back the protective red oxide paint to reveal bare metal, the tank was sprayed with etch primer

followed by 2 good coats of 2k high-build primer

which, after leaving for a couple of days, was flatted off prior to applying 3 coats of 2k gloss black (these are all applied during the same session as soon as the previous coat has flashed off)

which was then flatted with G3 rubbing compound and masked for pin-striping prior to carefully applying 5 coats of 2k gold paint (one side at a time) with a small brush. Finally, the pin-striping was blended in with G3 compound, the “Velocette” waterslide transfer slid into place and 3 coats of 2k lacquer applied.

Although it takes quite a bit of effort the end result is quite satisfying.

It has been a long journey for these tanks. Mr Sridhar, pictured below with me outside his workshop in the back streets of Bangalore many years ago

made these plus some other tanks (I wrote a few lines about this in a previous blog post some years ago). These are some pictures of the 3 tanks that I have used on the 3 recent Velo builds during their construction.

Works of art and fabricated with only a few simple hand tools.

Mr Sridhar: I have no idea if you are still working in Bangalore or if you have gone back to your home and family in Kerala. But if you or someone that knows you ever reads this then please accept my thanks again for the most beautifully crafted tanks.

In the meantime, the powder coated parts came back and after a few days the final build of KTT 55 was completed and it was time to fire it up. Starting a bike for the first time after a complete restoration is always a slightly nervous moment, especially when it has taken so much work.

Just to recall a few details about the engine build – most of the parts inside the engine are new: a complete new crankshaft and con-rod, lower bevel gears, crankshaft shock absorber assembly, piston and rings running in a Nikasil bore, new-manufactured O1 tool steel Oldham couplings, valves, guides, springs, collets, rocker skids, tappet adjusters, reground cam, new-manufactured cambox scavenge oil pump, all bearings, all fasteners, rebuilt AMAC TT carburettor and square ML magneto - in fact, apart from the castings, it is essentially a new engine inside.

Before firing up the bike I put in on the starting rollers with the spark plug out and motored the engine for a minute or so to get the oil circulating. The spark plug was then reinserted and with my wife as camera operator and my buddy JT helping with things mechanical it was time for the first start.

Not too bad. A bit of oil where the rockers exit the cambox (I had filled the cambox with oil during assembly) but otherwise oiltight and sounding crisp (or simply “loud” if you’re a neighbour).

The final step, for now, was to set the oil pressure. I have a 0 - 30 psi pressure gauge that I acquired many years ago to set up the oil pressure on a KTS and that is attached to a length of hose and a K99 Inspection Plug that screws into the upper bevel gear housing, modified with a 1/8” BSP internal thread, to measure and set up (using the K69/2 adjuster) 12 psi oil pressure. I cable tie it temporarily to the handlebars for convenience. The oil return to the tank was of course checked and was good.

So, that’s about it until road testing starts. KTT 305 is now being prepared for a first start.

A Blast from the Past

A reader of my blog recently sent me this link – now many years old – about a bike that I had restored 20+ years ago and so I thumbed through my old pictures (relatively low-res by today’s standards) to remind myself what I had done.

I bought 2 bikes, a Matchless G80CS (the Competition Model of the 500cc single) and a Velocette KTS from a vendor somewhere in Wales. These are the 2 bikes in my workshop shortly after their acquisition.

 Both bikes underwent a complete mechanical and cosmetic restoration.

The all-alloy Competition Model G80CSs are fairly rare, especially an early one such as this with the magneto behind the cylinder – AMC moved the position to the front of the cylinder shortly after this one was made – same as the AJSs.

The Velo also turned out OK

and both were a pleasure to ride although I recall the KTS being quite heavy for a 350.

It seems the Matchless is in New Zealand and Petr from Czechia (Czech Republic) contacted me recently to say that he now has the AJS M10 that I sold last year in a Bonhams auction. Petr has a well-equipped workshop and has done quite a bit of work on the bike – adding a lighting system, more comfortable footrest position etc,

quite probably required to be road-legal in Czechia.

I was looking for a file on my laptop recently when I came across a movie that was my one-and-only attempt at using a bike-mounted camera. Out of curiosity I bought a camera some years ago and tried it out at the Manx GP in 2016. This is an attempt to film a trip from The Bungalow heading down the mountain on the A14 (it’s a back road) in the direction of Sulby Glen. I was riding my 1928 flat-tank Norton that I had restored some years earlier (see HERE), this one,

and it’s probably feasible to work out the engine rpm from the frequency of the vertical bouncing of the picture.

….and with narrow tyres you have to avoid hitting a cattle grid at an angle and scaring the sheep that wander around and that can be a bit unpredictable with an open pipe exhaust.

Last, but not least, this short movie clip shows the AJS K7 that I rebuilt some years ago participating in a hill climb event.

Ian Hatton, the proprietor of Verralls, is riding the bike which is for sale at his establishment.

Final Builds of KTT 305 and the DOHC 250

It took a bit longer than expected to complete the final build of the DOHC 250 because the UK (and much of Europe) has experienced temperatures normally associated with the Sahara desert for many days and it has been impossible for certain jobs to be completed. Anyway, the final builds of the first 2 bikes, KTT 305

and the DOHC 250,

are now complete. I have not made any attempt to start either of these yet – that will have to wait until after the final build of the 3^rd bike, KTT 55. There are also a couple of minor jobs yet to be done such as adding oil (!!) and setting the vertical position of the remote float chamber on the DOHC 250 to get the correct fuel level on the downdraft RN carburettor.  

Why has it taken a bit longer to complete the DOHC 250? Well, my powder coater first has to grit blast all of the components and he does this in a confined space (rather than a blasting cabinet) so that he can blast large structures such as a complete vehicle chassis and he dresses in full protective gear. This is a photo of the graphics from the side of his van

and it would be unreasonable to expect him to be working dressed like this in an enclosed space in the recent extreme hot weather when my car is registering 36⁰ C ambient temperature and I’m sitting in the shade of a large apple tree in the garden drinking cold beer. 

There were quite a few more bits and pieces to go in the plating bath for the DOHC 250, mainly due to the number of external oil pipes.

The parts to be chemically blacked were completed,

the exhaust pipes for the 3 bikes came back from Dorsetware after chrome plating and polishing (they have made a stunning job and highly recommended),

the petrol and oil tanks were painted in the back garden

and the bike reassembled.

So, the last bike in this batch of 3, KTT 55, is now up on the bench for the same treatment.