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 projecst so far.

In August last year I acquired a DOHC 250 Velo Engine. I have completed the rebuild of this engine and the dry build of this bike is also finished. Details of this project can be found in the links in the 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 existing 3 Velos - full details of the project so far in the links here.

I have now started on the final builds - painting, plating and powder coating of the 2 KTTs and the DOHC 250. The first of these is KTT 305, which has been stripped into its component parts (except the engine and gearbox, which are finished), and all the metal finishing is well underway.

In the most recent blog I have described progress on the plating, painting and chemical blacking.

I am now waiting for the powder coating to come back to start putting the bike back together.

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.

Completing the Build of KTT 305: Part 2 – Metal Finishing

So far, I have stripped the bike, segregated all the bits into boxes and sprayed the frame, forks, petrol and oil tanks black – see previous blog. However, there is a still a lot of work to be done in finishing the petrol tank (pinstriping. “Velocette” insignia etc) and putting “something” on the bare metal of all the other parts. There are also decisions to be made as to exactly what that “something” will be…

I have a few general rules for this; in no particular order:

      -       2k paint for the petrol and oil tanks

 -       Plating – for this era of bike I use chromated zinc plating rather than nickel (up to around 1928/9) for shiny parts

 -       Chemical blacking for parts for which it is important to retain the as-manufactured dimensions

 -       Chrome plating for post-1928/9 bike exhaust pipes

 -       Powder coating (gloss black) for the myriads of little bits and pieces that make up most of the bike

As these are my rules, I can break them! For this bike I already decided to also paint the frame and forks (rather than powder coat) – see previous blog – so that I could use high-build primer to smooth out some irregularities, but the parts for the rest of the bike have otherwise followed this format.

Please bear in mind when reading the next part of this blog about painting that although I have been putting paint on motorbikes for around 60 years (see here) I am not a professional painter and there are probably some alternative ways of achieving the same end; anyway, what I’m describing seems to work for me.

The first step in preparing the tank for pinstriping is to define the pinstripe with a piece of masking tape that is the same width as the pinstripe itself (It is useful to have masking tape in a selection of widths)

This will not follow the curve on the inside of the tape at the front of the tank (the outside of the curve is fine) – the curve is too tight - and so some judgement is needed for the next stage to maintain a constant width in this region when the pinstripe tape is bounded on both sides with very narrow masking tape (which does follow the tight curve).

The wider tape is now removed

and the part where paint will be applied is carefully rubbed down with 800 grit wet-and-dry paper cut into thin strips from an A4 sheet and using a thin piece of wood (this is a piece fashioned from a wooden garden plant name tag).

I have now applied 2k gold paint using a fine artists brush, rubbing between coats; this is quite time consuming because the paint needs to cure sufficiently between coats and I can only do one side of the tank at a time. I have put on 5 coats to avoid the black showing through.

The tape is now removed, the entire tank is rubbed down with 1200 grit wet-and-dry and the Velocette waterslide transfers are carefully affixed.

The transfers come from Classic Transfers who have been in this business for many years and, in my experience, one could not wish for a higher quality product.

It’s then back in the garden to apply 2 good coats of 2k lacquer.

It is very important to first spray 2 very light coats of lacquer on the transfers, separated by a 15-minute interval. If this is not done there is a good chance that the transfers will “crinkle up” and spoil the appearance.

After leaving the tank a couple of days for the lacquer to cure I have then flatted it with 1200 grit paper followed by polishing (I use a DA9 Dual Action polishing machine) with, firstly, G10 rubbing compound followed by polishing with Meguiar’s Carnauba polish.

Not perfect (one always sees one’s own imperfections!) but not too shabby.

By the way, if you happen to have a cylinder of Argon gas in your workshop (which I do, for TIG welding) then I always give any open tins of paint and hardener a short blast of gas before putting the top on the tin. 2k paint seems to last indefinitely anyway but hardener doesn’t, once opened, and other paints and varnishes will not form a skin if they are shielded by the inert heavier-than-air Argon gas.

I described some years ago the plating and blacking processes that I use, so only a brief summary here for this bike.

For the shiny bits, the zinc plating bath is set up

and, after polishing each part, scrubbing with “VIM” (an abrasive usually used for cleaning household sinks) with a toothbrush, fondling with soapy hands and rinsing in clean water the parts are plated for around 3 - 4 hours.

After plating, each part is washed and then dipped into another bucket containing a blue passivate solution that converts the zinc to zinc chromate.

After rinsing and polishing, these parts are finished. The picture below shows some of the copper oil pipes for KTT 305 plated in this way.

The finish is not as bright as chrome but I’m quite happy with the appearance as it is not too shiny and “blingy” for a vintage motorcycle.

The chemically blacked parts are treated using 3 separate liquids – see here.

Last, but by no means least, the exhaust pipes for all 3 bikes

have gone to Dorsetware for chrome plating. They do all the plating for Armours (who bent these pipes) and with whom I have only ever had good experience. It will be a few weeks before these come back but I have plenty to do in the meantime.

And all the remaining metal parts have gone to Autoblast for powder coating.