Thursday 18 June 2020

The AJcette Project ….how it started

There are plenty of things in a workshop that can be dangerous. Large pieces of metal spinning round in a lathe chuck, milling cutters, disk cutter and other sharp tools; there are poisonous liquids – I use cellulose thinners for parts washing, 2K paint, methylene chloride for removing old tank sealer, all of which are very nasty chemicals and, of course, there are hot things from welding or heat treatment that will burn your fingers nicely! Accidents do happen, but if care is taken you can get to the end of each day without ending up in A & E.

There is something else that is not usually thought of as being dangerous but, nevertheless, can easily take a year out of your life. And that is having a bit of spare time to sit down and let the mind wander. Whilst I was restoring the K7, in a moment of idleness I mused “I wonder if I could convert my side-valve 350 AJS to overhead cam” ….and that was how the AJcette project started ....and another year went by.

Sometime previously, I had bought a 350 side-valve AJS on ebay. It was in Scotland and, as I live on the South Coast of England, was a long drive to go and pick it up. When I got there, it turned out to be in very original condition, non-running, no registration documents and, for some reason, somebody had painted it in cheap and very bright red paint. They hadn’t made a very good job of the brush painting, the mudguards and tank had been painted “in situ” without even cleaning the dirt off!

Luckily, the artist that had painted the bike had used some cheap household paint that simply wiped off with a rag soaked in cellulose thinners to reveal what was almost certainly the original enamel beneath.

One valve spring had broken and, as these are conical valve springs and I didn’t have anything that even closely resembled one of these in my workshop, I TIG welded the 2 halves of the spring together and, amazingly, it worked fine for a few hundred miles until I eventually sold the engine. I would not do that on an OHV engine! I found that the bike was good for about 46 mph flat out with me lying flat on the tank and clocked by the speedo of a following Velo; even that speed is probably optimistic.

As far as I can ascertain, all the AJS 350s of this period (1920s) had the same frame/forks/hubs/gearboxes etc (although ratios are different between SV and OHV/OHC bikes). This would therefore make an excellent starting point for a K7-lookalike …..I just needed an overhead cam engine and close ratio gears.

This story is about how the bike pictured above turned into this:


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