Years ago I bought a 1950's Hercules bicycle at an auction (a proper one where you go and wave your hands about) and I've been thinking lately that it needs a little more... excitement. So I have bought this at a very good price on the Bay of E:

That's right! it is a Cyclemaster! It is from 1952, and sports 26 cc of 2-stroke technology giving 0.6 bhp of raw grunt. It is very original, with it's original Dunlop Carrier tyre & rim, and it's original control levers. It is however, or appears to be, seized.

Take a look at this splendid film:

This information from The Moped Archive is helpful and confirms that wheel number A63643 would have been manufactured in 1952, since in April 1952 Cyclemaster Ltd. had built 50,000 units and 100,000 had been built by the end of 1952:

There is an excellent site about Cyclemasters at

The Cyclemaster has been in the workshop for a look over. It is remarkably original as I had thought; it has a coaster brake and is a 26 cc model, but it has been some while with the spark plug loose and is seized solid.

Here are a few more pictures. I have the Cyclemaster trial fitted in the frame now:

The bracket tying the engine to the bicycle frame is missing, so the engine is free to turn:

We'll have to make a new one:

But all that is a bit secondary, because the engine is seized. After about a 9 months with oil in the bore, I have some spare time at Christmas 2014. Time to strip the engine again.

Sweet little engine
Drive sprocket looks good. This machine has not seen much use.

This time, a few minutes work with a large socket in the bore, some more oil and a 2 lb engineers hammer reveals this dinky little piston, with the rings stuck fast. Those will not be coming out!

Oil & scale
The bore is unmarked, and hones up nicely

No damage here
So, putting it all back together we can test it on the power drill

So, that reveals that the magneto is merrily sparking away, so we can get on with the rebuild in order to get it running. The rings are stuck fast, so we will remove the piston in order to dig the rings out of their grooves and replace them. The gudgeon pin cleans up nicely with 1200 grit wet and dry.

Sweet little connecting rod. The big end feels fine, and the mains seem to be solid too. small end bush is good.

Pulling off the side of the crankcase allows us to clean out rusty sludge from the crankcase:

Disc valve grubby but intact

Lovely casting quality

Time to remove the rings. They both come out, in small pieces. I have ordered a new set today from Mopedland.

Piston ring kit. Glue & paints not included

And today I have joined the EACC and IceniCAM. But while we wait for the rings we need another job. Time to clean the carburetter. 20 minutes in the ultrasonic bath at 60 degrees C cleans out all the muck:

It so small we are using our watch repair tools to rebuild it!

We'll need some new gaskets:

Use a sharp pencil
Punch the holes
Cut the inner diameter
Trial fit
Cut the outer diameter

Just after New Year the new (old stock) rings arrive from Danny at Mopedland. Excellent service!

Quickly fitted around their pegs, and tried out in the bore before assembly (don't push the piston too far in. The rings will get caught in the ports unless you are careful to orientate them correctly!

All back together, assembled with Threebond (no paper gaskets required) and with the barrel re-blacked.

OK, next step is to clean up the wheel and put the engine back in. That done, I can make some new brackets to attach the engine suspension assembly to the frame:

We will tidy those up when we are sure that they fit. Now we need some cables

32 spokes in the front wheel...

And here it is on the grass track:

So, having joined the EACC, I can move on with getting it registered. But first I need some tinware. I have a mudguard, but I need a number plate. We also have a 1950's carrier, which needs some brackets, and the mudguard stays are too short, so I will have to make some new ones; the list goes on.

Starting with the number plate, we will cut out a blank from a sheet of 18 SWG cold rolled sheet bought from eBay for the Bantam project. Using a power jigsaw we cut out two rectangles, one for the number plate and another for its mounting bracket. The third piece will be a clamping bar for the carrier:

Then, using rudimentary tools (hammers and bits of bar stock, along with a vice and a socket) we can roll the edges and round the corners. Fold each edge gradually; the two long edges first, to within 3/8" of the corners, followed by the two short edges again to within 3/8" of the corners. Clamp a socket into the first corner and use the hammer to fold the edge around the corner. When you have done all four, finish the edges to 90 degrees. File off any roughness:

And using files and those rudimentary tools again we can make a little bracket for the bottom of the number plate:

And then we need a mounting for the top. I wanted this to look like a '50's aftermarket accessory, and using some 4 mm round section and some sheet offcuts I came up with this:

It mounts like this:

Or, with a bit of adjustment, like this:

The bracket at the bottom will mount onto the mudguard stay screw. The next job is to weld it together with the MIG set. You can see we have the carrier in place now.

My welding needs a lot of practice. Unfortunately I ran out of CO2 and used Argon instead, but the main problem was light & a poorly aimed torch. Here it is again, fitted and painted:

And here is the whole machine. Coming together:

I have this jolly nice period Butlers rear lamp:

And I have an equally nice Sturmey Archer front lamp, which ought to go with a Dynohub:

Dynohub technologies are described here.

The brakes are now connected again:

Braking technology '50's style
New screws are readily available in the right threads, but period screw head shapes and finishes are much more difficult...

Its now late May 2015, and the V5 is back from the DVLA. I'd applied using a dating certificate from the EACC, and as usual the DVLA have come up with an age-related registration in about 10 days. The bike is MOT exempt and the tax is free, but when you get your new V5 you will need to wait up to 48 hours for the new registration number to filter through to the MOT database. When it does, you can tax the bike, which is free:

So, we can get on with making the bike roadworthy. I have some number plate letters on the way, but there are a few jobs left. There's no oil in the clutch housing, so its off with the magneto cover to expose the filler plug. The clutch housing filler plug is just a 1/2" BSP taper plug which comes out easily with a large screwdriver:

Apologies for the poor picture, but I need flash to see inside the clutch housing. The chain looks good, but there is no oil in there...

The CycleMaster instruction manual tells you to use SAE 140 gear oil. This useful non-EP oil is, surprisingly, readily available. EP additives are not good for gearboxes with bronze bushings, which most Burman boxes are equipped with, so this oil might be useful when I top up the Ariel's gearbox:

As the book says, when the clutch housing is empty you use the petroil measure under the fuel filler cap to measure out 50 cc of oil for the clutch housing. You can get it in without too much mess.

So, only the insurance to do now, then we can have a go on it!

A few days later and its a sunny day at the beginning of June 2015. We have a new number plate:

So what's it like to ride? Well it starts and runs quite happily, but it couldn't pull the skin off a rice pudding. I've done about 4 miles so far on new rings so I expect the compression is pretty low; the exhaust is also leaking. Wonder where I can get a tiny fibre/copper gasket?

A few weeks later and the exhaust is off. I can't blow through it:

Louis Armstrong moment
So it's out with the MAPP torch, heat it to red all over and burn out that carbon. Lots of acrid yellow smoke form the engine end; nothing from the exit... Heating near the fishtail seems to produce smoke from both ends though, and when it has cooled down, we can blow through.

Its brazed and welded construction, for future reference:

Brazed connection
More like a Recorder player now...
A quick spin around the garden shows lots of exhaust smoke from the fishtail, and a rain-soaked run on the road a few days later was a right laugh! Lots more power, and it even goes up hills with a bit of 'Light Pedal Assistance'!

The CycleMaster is now sold, soon to become a distant memory. It's stayed in Norfolk though!


  1. Lovely tale. It reminds me of when I (perhaps foolishly) decided to do a ground-up restoration of an NSU Quickly. Beautifully designed and engineered little machine but a little like your experiences, when I'd finished it was absolutely gutless despite having a clean exhaust. I even thought I'd put the piston in backwards, but no....

    So off it went to Bonhams, losing me a small amount of cash in the process.

  2. Ah, I had one of those, fitted with a speed on driven off the front wheel. Used it to commute between Reading and Henley-on-Thames. Tried tuning it a bit and got it up to an indicated 31 mph going down Span Hill . After that it rattled a bit and discovered that the flywheel had stretched and all the spokes were fractured but still able to drive the rim. Often wonder how many rpm that was to cause that?