Vintage Thing No.100 - Tarkus
Tarkus is the title of a 20 minute Emerson, Lake and Palmer prog rock epic describing the three battles of a turret toting armadillo on caterpillar tracks by the name of Tarkus.
But of course I knew nothing of this until recently, being a punk rocking gear head. To me, Tarkus was the grandaddy of all Citroen hill climbing trikes.
The existence of the hillclimbing Tarkus had often been mentioned just within my earshot in hushed whispers as I stalked around the Cornish hillclimb paddocks and pits. It was always in connection with a fire breathing supercharged Citroen powered trike called Kermit. Gradually, I pieced the story together and discovered that Tarkus was the inspiration behind Kermit.
Tarkus was built by a chap with the suitably heroic name of Jake Challenger and is actually one of six. The very first one was originally designed around a two-stroke three-cylinder engine from a DKW (Vintage Thing No. 13).
Jake described Tarkus as being designed and built on a shoestring but this simply gave rise to more ingenuity. The Deek engine was highly modified to the extent that it was more of a Challenger than a DKW..
Jake eschewed the DKW transmission and used a Norton box driving a Mini diff by chain. This allowed him to mount the engine transversely.. He cut off the standard Deek barrels and substituted them for steel ones he made himself using the dimensions and porting of an AJS Stormer two-stroke scrambler engine.
AJS Stormers were two stroke single scramblers of 368cc using a a bore and stroke of 83 x 63mm. Later versions were 400cc (83 x 74mm) and put out 37 bhp - less than the Japanese rivals but delivered in such a way that only a four-speed gearbox was a required when a six-speed was common, allowing the average clubman to achieve better results than on a peakier machine.
Jake made his own head, starting with a plate that he machined up with bolt holes, water ports and three combustion chambers with the squish bands he wanted. This was then incorporated in a casting that gave the head its water jacketing - all a pretty tricky process but I gather this went very much to Jake's satisfaction.
The engine re-design meant that Jake had to stagger the ports, with one expansion chamber running forward with the others going backwards. Even then, the passenger had to kneel for the engine would have been in his or her lap and the engine was pressed up hard against the driver's leg. Jake described the expansion chambers as "the size of wheelie-bins" and "my God it was loud!"
All this work gave an engine that displaced 1300cc - something along the lines of 83 x 78mm (AJS bore with the DKW stroke) to give 1266cc. Factor in three lots of 37 bhp and you get an idea of the power available (111bhp!) in a very lightweight package.
Jake completed Tarkus in 1975/6 and used it often at Curborough, also going circuit racing with it.
If anyone can put me in touch with Andrew Eason, who wrote briefly about Tarkus in the Old Bike Mart of August 1999 and provided the above image, I'd be very grateful. I'd like to ask him about this and another special three wheeler he featured in his letter, a Velocette powered machine called the Howcette.
But the Tarkus I'd heard about was Citroen powered.
This was because, after about 3 years, Professor Challenger re-worked Tarkus to accept a supercharged flat four engine from a Citroen GS.
Initially he wasn't all that impressed with the flat four engine. It was chosen because a friend in the trade had a ready supply of them but Jake reckoned the pistons were too heavy. Smaller slugs lowered the compression ration too much because these motors are very much hemi-head affairs with high domed pistons. It was largely because of this Jake decided upon using a supercharger.
It was this spec that inspired Phil Williams to build Kermit and later Luigi, and Alfa-powered version.
The original Tarkus was at last sold by Jake to make way for another trike also called Tarkus and also featuring some Citroen parts, of which more later. In all he made six but this one, the first of the lot, eventually ended up with David Low of Lomax fame, who'd bought it only because the trailer that came with it was specifically built for three-wheelers. For some time, Tarkus No.1 languished in the workshop at Lomax until they used parts of it in an attempt to use the American Super Vee engine in their Citroen based trikes but all that is another (other) story.
So this machine - the very first Tarkus - is really the root of a strange family tree of obscure Citroen-based specials with a strong competition links.
But here's an odd thing. If you search Tarkus trike on the internet, you will find a prog rock criticism blog that features ELP's epic among many others. It's called Mystery Tricycle and describes itself as "obscenely pretentious taste in music".
Me? I prefer the visceral sounds of garage music and howling spannies and cackling blown flat fours.
But of course I knew nothing of this until recently, being a punk rocking gear head. To me, Tarkus was the grandaddy of all Citroen hill climbing trikes.
The existence of the hillclimbing Tarkus had often been mentioned just within my earshot in hushed whispers as I stalked around the Cornish hillclimb paddocks and pits. It was always in connection with a fire breathing supercharged Citroen powered trike called Kermit. Gradually, I pieced the story together and discovered that Tarkus was the inspiration behind Kermit.
Tarkus was built by a chap with the suitably heroic name of Jake Challenger and is actually one of six. The very first one was originally designed around a two-stroke three-cylinder engine from a DKW (Vintage Thing No. 13).
 |
| Tarkus - small loud and very fast. I love the matching helmets and those two stroke expansion chamber stingers spreading out over the nearside flank. Ear plugs were a necessity. (Photo Jake Challenger) |
Jake described Tarkus as being designed and built on a shoestring but this simply gave rise to more ingenuity. The Deek engine was highly modified to the extent that it was more of a Challenger than a DKW..
Jake eschewed the DKW transmission and used a Norton box driving a Mini diff by chain. This allowed him to mount the engine transversely.. He cut off the standard Deek barrels and substituted them for steel ones he made himself using the dimensions and porting of an AJS Stormer two-stroke scrambler engine.
AJS Stormers were two stroke single scramblers of 368cc using a a bore and stroke of 83 x 63mm. Later versions were 400cc (83 x 74mm) and put out 37 bhp - less than the Japanese rivals but delivered in such a way that only a four-speed gearbox was a required when a six-speed was common, allowing the average clubman to achieve better results than on a peakier machine.
Jake made his own head, starting with a plate that he machined up with bolt holes, water ports and three combustion chambers with the squish bands he wanted. This was then incorporated in a casting that gave the head its water jacketing - all a pretty tricky process but I gather this went very much to Jake's satisfaction.
The engine re-design meant that Jake had to stagger the ports, with one expansion chamber running forward with the others going backwards. Even then, the passenger had to kneel for the engine would have been in his or her lap and the engine was pressed up hard against the driver's leg. Jake described the expansion chambers as "the size of wheelie-bins" and "my God it was loud!"
All this work gave an engine that displaced 1300cc - something along the lines of 83 x 78mm (AJS bore with the DKW stroke) to give 1266cc. Factor in three lots of 37 bhp and you get an idea of the power available (111bhp!) in a very lightweight package.
Jake completed Tarkus in 1975/6 and used it often at Curborough, also going circuit racing with it.
 |
| Here is Tarkus, this time without a roll bar, at Cadwell Park in May 1978. Note the three carbies that sucked hungrily at the pilot and passenger. (Photo Andrew Eason via the Old Bike Mart) |
If anyone can put me in touch with Andrew Eason, who wrote briefly about Tarkus in the Old Bike Mart of August 1999 and provided the above image, I'd be very grateful. I'd like to ask him about this and another special three wheeler he featured in his letter, a Velocette powered machine called the Howcette.
But the Tarkus I'd heard about was Citroen powered.
This was because, after about 3 years, Professor Challenger re-worked Tarkus to accept a supercharged flat four engine from a Citroen GS.
Initially he wasn't all that impressed with the flat four engine. It was chosen because a friend in the trade had a ready supply of them but Jake reckoned the pistons were too heavy. Smaller slugs lowered the compression ration too much because these motors are very much hemi-head affairs with high domed pistons. It was largely because of this Jake decided upon using a supercharger.
It was this spec that inspired Phil Williams to build Kermit and later Luigi, and Alfa-powered version.
 |
| It's a thing of beauty isn't it? If you can tear your eyes away from the powerplant, look at the wishbones. More about them another time in connection with yet another Vintage Thing (Photo Jake Challenger) |
The original Tarkus was at last sold by Jake to make way for another trike also called Tarkus and also featuring some Citroen parts, of which more later. In all he made six but this one, the first of the lot, eventually ended up with David Low of Lomax fame, who'd bought it only because the trailer that came with it was specifically built for three-wheelers. For some time, Tarkus No.1 languished in the workshop at Lomax until they used parts of it in an attempt to use the American Super Vee engine in their Citroen based trikes but all that is another (other) story.
So this machine - the very first Tarkus - is really the root of a strange family tree of obscure Citroen-based specials with a strong competition links.
But here's an odd thing. If you search Tarkus trike on the internet, you will find a prog rock criticism blog that features ELP's epic among many others. It's called Mystery Tricycle and describes itself as "obscenely pretentious taste in music".
Me? I prefer the visceral sounds of garage music and howling spannies and cackling blown flat fours.
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