Old Bike Australasia

The Z Special

Around 1953, Sir Carruthers Spagforth received a formal letter from Mr Fred Slammer, the owner and chief designer of Z Special Motorcycle­s, regarding any possible interest in purchasing the manufactur­ing rights to his design, which featured a side inlet v

- Edgar Jessop

“We wanted to combine the sluggishne­ss and heavy petrol consumptio­n of the side-valve with the complicati­ons and shattering expense of the cammy design,” explained Mr Slammer. “We have succeeded admirably, because the Z Special is a vile, lumpy engine and never manages more than 35 m.p.g. You will note that the connecting rod is built up from curtain rail and Balsa cement. That gives appalling bulk with precious little strength. We rely on a plain big-end. By plain I mean that the con-rod bears directly on the crankshaft with no bush at all. It squeaks a bit and seizes every fifty miles, but look at the money we save.

“The crankshaft is flexible and when the engine first starts, the crankshaft remains true. As the speed of the engine increases, the shaft flexes and the piston travels higher and higher up the cylinder, thus increasing the compressio­n ratio. The dynamo is under the saddle, out of the way of extraneous road water and dirt. The readily accessible battery is a car type, so one can leave the lights on all night with impunity. The exhaust system not only heats the saddle, but, by reason of its many curves, creates considerab­le back pressure. The gearbox has a commendabl­e habit of rotating in the frame. This is very useful for draining out the old oil. The rotary motion also sets up a draft which cools the gear clusters. For the MkII version which is presently on the drawing board, I plan to substitute proggling iron in the con-rod in place of the present curtain rail, with snogger wheels to form the big-end bearing.

“The proven fact that internal combustion engines run better at night due to the high water content of the atmosphere has prompted me to fit a funnel to the petrol filler cap so that rain water is introduced to the fuel. The camera mounted on the front of the machine supplies evidence I am compiling on the life and death of the jay walker. The rear light has been augmented by the addition of an older, but reliable, type of oil burner in a neat nacelle. The tyre saver seen at the front is my own design. I respectful­ly submit that the Z Special is indeed the world’s most interestin­g motorcycle.”

Both Sir Carruthers and Edgar Jessop, who had been invited to the meeting, considered the propositio­n deeply, shooting glances at one another before the guvnor delivered a carefully worded reply. “As the Z Special very closely replicates the existing Spagforth Lurcher, notably in the utilisatio­n of a double edged bobbleweig­ht which exactly matches the inertia of the wooble gear on the primary rotating column, I shall be seeking expert advice on the possible breech of Spagforth patents.” With that, Edgar briskly escorted Mr Slammer off the premises. Nothing further was heard of the Z Special, although a machine with similar technical features was later marketed as the Ariel Pixie.

“The tyre saver seen at the front is my own design.”

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