Vintage Thing No.114 - Velocette MOV

This man is going to buy something with two wheels and very soon

This little bike caught our attention at Wiscombe Park. Most things in black and gold do but Pete had some cash burning a hole in his pocket (which has now become a Matchless single) and we began to have covetous thoughts about Velocette 250s.

Of nearly square dimensions (78 x 78.5mm), the MOV is a rev-happy little chappy. According to Titch Allen in his splendid book The Velocette Saga, David Holmes developed his MOV to spin up to 10,000rpm and subsequnetly reduced the rev range to 8,500 to provide more useable power on the race track. It must be nice for the rider to know they're nowhere near the bloodline when they're ringing its neck. It would still do 100mph, and although it's a production bike, the Suzuki X7 was billed as the first ton up 250 when that was introduced in 1979. That would be 30 years after the MOV went out of production and - of course - the two bikes are not really comparable as one is a highly developed vintage racer and the other isn't.

The MOV was introduced in 1933 and was the first of the famous pushrod singles. Throughout its lifespan it had Webb girder forks (made to Velo's specification) and a hardtail but the performance crept up from just over 60mph to over 70 mph. 

The MOV was an outstanding design and proved to be the saviour of Velocette, along with its 350cc bigger brother, the MAC, which came a year later. Both had the narrow, and consequently very stiff, crankcase and the weird Velocette clutch that works well in practice. It was the work of Eugene Goodman and Charles Udall and grew out of an abortive effort at a 350 side valve machine, which contributed its frame to the new project. Although aimed at mass market acceptance, certain features hinted at potential performance such as the high camshaft design and the "square" cylinder dimensions.

The "map of Africa" timing case contains the gear train for the valves and makes the engine look a stumpy, purposeful powerplant, not a like the tall and sometimes elegant singles of the vintage era

Titch Allen attributed part of the MOV's success to care full timing gear design. Originally these were straight cut but production versions went over to more expensive helical gears to reduce noise that became apparent with thinner production crankcase castings. Thicker castings might have achieved the same affect but that was not the Goodman or Udall way. Another aspect was the valve gear, which was enclosed, had pressure lubrication and decent sized bearing surfaces. It was also designed to be light and Udall went to great pains to avoid valve springs breakages, which at the time were an accepted part of motorcycling life - "they all do that, squire."

Titch subsequently developed an MOV into a very effective VMCC racer, simply by getting a mate to turn off some metal from the bottom of the iron barrel to increase the compression ratio and boring out the inlet valve throat himself with a Victorian drill.

The slightly less glamorous drive side of the plot still looks sporty to me. Note the catch tank - it's Pimms o'clock!

The MOV lasted in production until 1948 when Velocette were working on their own take of an "everyman motorcycle", which became the side valve LE twin. They were overlooked for many years as 250 vintage racers were well supplied with Rudges, OK Supremes and New Imperials (what trade names these bikes had!) but during the fifties interest began to switch to 250cc MOVs. An East London motorcycle dealer by the name of Woods even marketed the ultimate go-faster goodie in the shape of an alloy head but these are not eligible for VMCC racing but David Holmes made do with the cast iron type, which work very well on methanol based fuels. His MOV ultimately produced 29 bhp on the back wheel at 8,500rpm on the LEDAR dynanometer but that was after years of development work that contributed home made cams (home made in the sense of a very well equipped home workshop), DIY magnetos to cope with the much higher revs, steel flywheels and a belt primary drive that runs inboard of the Velo clutch.

What caught our eyes about this little Velocette was its obvious rightness. It's small and light but the riding position still looks reasonably comfortable to me  for a gallop up the hills. That engine is so compact, too, it looks like it should rev and being a Velo it should handle well, too. I would prefer more modern forks and a rear spring arm but Pete Low - who actually knows about these things - says it would handle quite sweetly as its is.

This particular Velocette MOV was campaigned by Dave Downer at Wiscombe and although we didn't see him to ask I bet he had a good time with it.