The 1957 Works Ariel Colt,

200 cc trials bike.



Ariel Colt trials.



This is the story about the Little 200cc Ariel Colt trials bike created by the Ariel competition department for World famous road racer to use as a fitness weapon.

There are several accounts  to what happened to the machine.

but after doing a bit of homework, I think it ended its days in the Isle of Man.

And was ridden by the newly formed branch of the Vintage Motorcycle Club on there inaugural trial by several members.

it may still be still be in existence there.

 Anyway here is the story from the Ariel club magazine from the year 2000.






Here is that picture from,

Motor Cycling 6th September 1956.




So this proves that the frame was actually a modified Ariel Colt Plunger frame.

And it looks to me a lot like it could be a modified D3 BSA Bantam Subframe.

It was reported to be gutless and threw big-ends but I am sure that today both problems could be overcome.

"Odgie Dannan" built a C12 BSA that was a lot like the Colt, and he rode that to some success,to well because it was eventually banned has the Class description was changed.


More later with an interesting update.




It transpires that the frame for the one off Works 200cc Ariel Colt, was a frame drawn up by Roger Barlow in the Selly Oak drawing office. 

 So was the frame built from scratch and a truly one off. or was the frame for Ariel registration number SON198, built out of bends of tube and cast lugs already available from the Ariel BSA factories.

Geoff Duke was entered on the bike to ride in the 1957 SSDT,

 but through an injury to his wrist, in a road racing accident he had to nurse that injury to keep his place in the Norton road racing team. as this was his first priority.

 This meant that Ariel had to decide quickly to get a replacement for their 250 cup challenge in the Scottish trial.

 the nominated replacement was  Clyde Bell.

 But there seems to be little information into what really happened in the event all we know there were problems with the machine and the machine got as far has the Friday before retirement, with a tale from the IOM fairies.

Going back to the Colt engine, one of the major problems with little power plant was that the oil supply was just not up to the job and this contributed to the reputation the engine had for throwing "Big-Ends"

If you take a close look at the photo of the bike you can see that some effort had been made on this works bike, by fitting external rocker oil feeds from the return feed, not unlike its big brother the HT5.

Photo Courtesy Deryk Wylde ORR. A Don Morley photo.


You can see that the bike was a bit of a "Hotch-Potch" in that it has a valenced alloy rim on the front wheel and a steel rim on the rear.

And one of the major issues must have been the ignition system.

 It must have been coil? as the alternator seems still to be fitted (or was the cover there for the extra flywheel?) so there must have been a battery under the seat area?

The bike just throws up more and more questions. and the biggest one what happened to it.


Being Ariel Works property, was it conveniently scrapped by the works or did Geoff take it to the Isle of Man with him?

 perhaps we should start a search for the little machine on Mona's Isle?



 More later and the connection to the BSA version of the machine.


You can see from this photo of a production Ariel Colt that the Plunger frame if converted would have needed a fair bit of work, cutting and shutting, to convert it to swinging arm.

Here is my theory. or the way I would have done it at the time. {the better photo of a frame below gives a clearer view of proceedings}.


So we are in the Ariel Comp shop at the time,and we have walked around the factory sourcing frame parts.

a front frame dimond is removed from the welders bench (ark welder that is). along with a set of forks from further up the line, the front frame , is thrown onto the bench and discussion begins.

 A suggestion is to pop along to the BSA development shop and see if they could borrow for want of a better word, one of the "New Triumph Cub" swinging arm castings and a swinging arm, that BSA were playing with for a new lightweight project they had on the cards (C15).

This casting was then set up on the Colt front diamond as per the drawings from Roger Barlow.

Pined into place, and then brazed.

Back around to BSA and a visit to the Bantam line, or better still the stores, and pick up a D3 subframe and a heavyweight BSA front mudguard stay, for use as a rear mudguard support.

A couple of days with three or four young apprentices with file and drill, and a working chassis complete with "Lyta" HT alloy tank, and "Lycette" saddle was finished.

A store-man had been sent off to Triumphs to pick up a cast Triumph Cub rear hub and that had been spoked into a WM 2 X18" back rim as there was not clearance for the preferred 19"rim,

The chosen Colt 200cc engine was built up in the comp shop by again a couple of skilled apprentices with a watchful eye of George chief Comp shop mechanic and even the interfering, new young Works rider Sammy Miller.

 And the adapted oil feeds for the rocker shafts were fitted along with a larger oil pump.

gear box remained at three speed but a strenghend clutch was fitted and a flywheel disc attached to the front engine sprocket.

Dead loss coil ignition was tried the charging element was just not working.

 also a Amal Monoblock 376 carb was used but jetting was atrocious.

All in all a Big little bike that was probably an experiment to far, in the fifties. and luckily its younger cousin came along young BSA C15T.

 And you would have thought that had the group kept going the New Ariel lightweight Trials bike would have been a re-badged BSA C15.

 Fact or Fiction? you decide.





 Not a good photo but this is the Dan Shorey Triumph Cub Race bike, and this frame was converted to swinging arm from plunger, just like the story above, and at the same time. 



Here you can see if the Colt frame was on the welders bench before putting onto a jig to attach the rear subframe. It would be an easy exercise to just slip the Triumph Cub casting up the seat-post to the drawing height, and behold you have a swinging arm frame.,with holes in the pivot pin to attach the subframe and footrest assembly.


So the conclusion for Now is that it was quite a simple exercise constructing the machine. But Why do it in the first place? when other parts of the same organisation, already had the Triumph Cub the works riders were experimenting with,and there was development work being carried out at BSA with a New bigger version of the Triumph Cub to be named the Model "C15, carrying on from the C10-11-and 12. as a smaller capacity to the A and B range of BSA's.

Although the gearbox was made by Burman, the mainshaft was designed to mount the existing BSA 'C' group clutch. The gearbox model number was GB30 until 1955 engine number LA1265 when it changed to GB33 to denote the introduction of a few changes. The only significant one was to the method of clutch adjustment, which was now carried out at the kick starter end of the push rod instead of at the clutch pressure plate.

Extract from Draganfly Motorcycles.


More Later ,with New information.