I was able to purchase this little two-stroke via eBay and I am yet to confirm its origins, while waiting for identification, I set about getting it going.
The first few jobs were easy, working out a way to attach the water jacket was sorted by using a spark plug reducer and some thick gasket material. The carburettor looks to be home brew made up off a few brass fittings, a float chamber was needed, and I was able to source a suitable Amal one from eBay. I expanded some copper pipe using an appropriate size socket and test fits were positive, with a bit of overzealous soldering, I had a complete carburettor.
I was lying in bed one night and had a thought… the piston didn’t have any anti-rotation pegs! This could be catastrophic for a two-stroke if the rings were going to move and spring into one of the ports while running. A little reluctantly, I had to come up with a solution. With a great deal of care, I drilled the piston for 6BA screws and installed screws with high temp thread lock before cutting to length. I also peened over the screws from both sides to do my best to convince them to stay in place (time will tell). I then fitted some new piston rings to suit, filing the ends to cover the pegs.
Ignition was the next hurdle, I first tried CDI units but that did little more than burn a hole in my wallet, so went down the trembler coil route. A brass wiper was made up to contact a little brass pin on an inboard pulley, I think this was originally for a belt starter, and I made up a trembler coil using a 5-pin automotive relay and car coil. This system produces a great spark, but for safety reasons, I won’t publish the plans here. At this point I was able to give the engine a test… after about 10 mins with a drill and messing with the slides in the carburettor I had some life! I felt a bit more confident carrying on with the engine now so forged ahead rigging up a water and small fuel tanks, no it doesn’t run on cold coffee…
After a few test runs, I concluded the points wiper wasn’t holding enough pressure, and the engine was dying soon after starting, running a bit like a Maytag but without the mass to keep it going. After some trial and error, I am now on a Mk4 ignition system, which I can adjust up and down to suit. It’s by no means pretty; it’s made from a bit I had in the shed, but it works. I have now run the engine for forty minutes to an hour, and it runs and starts quite nicely for a small two-stroke. It’s happiest between 750-1100 rpm. It is now rigged up with a small Stuart Turner pedestal pump to give it a bit of load.
All in all, not a bad eBay purchase, it would be nice to get an idea of who supplied the casting as the main bits look too good to be made from scratch by a home engineer, and the fit and finish of the ancillaries have a little to be desired but better than I could do. My additions add to the ramshackle looks of the engine…but it runs!
I keep meaning to paint the fuel tank and make up some straps, but the coffee can give me a giggle each time I see it.
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Country: GB
