1963 Mark IIB Super Shrike/Villiers 9E/4 manufactured by Motor Karts Limited

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Columns: Legendary kart
Motor Karts was one of a small group of English kart manufacturers that were involved in the beginning of British karting in the sixties. The company began trading in 1960 advertising a kart known as the MB Wasp sometimes referred to in race meeting programmes as the Em-Bee Wasp ((Text and Photos: Frank Weir)

At that time the business was devoted to mainly producing karts powered by the 197cc Villiers motorcycle engine with a 3 or 4 speed gearbox for what was then known in the United Kingdom as Class 4.  Motor Karts also advertised a chassis for Class 1 which was for direct drive engines not above 100cc; that kart was known as a Gnat. The company advertising on a few occasions in the karting press in those early days of trading used a photo of Bruce McLaren on his Wasp which he actually raced at tracks around the London area, Surbiton in particular.

  The MB Wasp was a ladder frame design influenced by the style of American karts of that time. The frame consisted of a dropped front axle, a live rear axle, two longitudinal chassis members, a seat back hoop and a steering hoop to support the steering column. The standard layout positioned the driver’s feet behind the front axle. An optional arrangement requiring an additional front porch to be welded to the front axle allowed for the driver’s feet to rest beyond the front axle thus facilitating taller drivers. Karting enthusiasts with do-it-yourself skills were able to buy a set of Motor Karts plans from which they could make their own Wasp.

Motor Karts was founded by L D S Clarke known to the karting community as Buster. On leaving school Buster became an apprentice at Hawker Aircraft. He then joined the RAF perhaps for National Service. After the RAF, Buster had a spell in the family jewellery business of Alexander Clarke.  Working in the jewellery shop bored Buster and he subsequently joined the Morgan Crucible Company as a trainee executive and in 1957 started the firm of Motor Books working under a gentleman called John Lelo. Motor Books did good business and in 1959 Buster left Morgan’s to start Motor Karts as a completely separate business from Motor Books although both company addresses featured at a time in Motor Karts advertising.

The very first customer for a production MB Wasp was a young engineering student called Chris Merlin. A short time later the second director at Motor Karts, a Mr McClelland, was bought out and Chris Merlin joined the firm and subsequently became a director. Merlin was not only a talented engineer but was also a very competitive and gifted kart driver. Merlin became the outright British Karting Champion in 1965 driving a Motor Karts Super Shrike IIIC.
Although their chassis manufacturing was farmed out, the small Motor Karts shop, cellar and back room in Kingston Road, Kingston, proved desperately short of space and Motor Karts moved to larger premises in Canterbury Park Road, Kingston, Surrey. The new location was said to look like a railway signal box. The work force at Canterbury Park Road consisted of Buster, Chris, Tony Dowe, Alan King, Jack Hubbard, Blackie Watts and Mrs Bliss.

The company had a racing programme which required a substantial budget to cover travelling, hotels and equipment. Such expenses were justified by proving their products in competition as well as allowing immediate design improvements and was also valuable advertising. Following every race meeting a debriefing session was held to analyse what had happened so that appropriate action could be taken.
Back then chassis production was undertaken by Allvic Engineering and batches of 18 were made at a time with parts intended for spares being ordered separately. It was reported that the standard of manufacture was very high and it was seldom necessary for a frame to be returned for rectification.
One of the firm’s principles was that owners of Motor Karts manufactured chassis or for that matter any other manufactured kart could update their non-current models. The company had a unique scheme whereby it was possible to buy all the components and frame of the latest model and fit the parts from an old kart and end up with the latest version on offer from Motor Karts. Initially for £40 a MB Wasp could be turned into a Super Shrike. The upgrade kit contained a primed and painted chassis with aluminium seat and undertray, upholstery, front axle, steering column, steering spade, pedal points, gear change lever, gear change rod, engine mounting beam, light alloy engine mounting plates, spacers, and bearing plates, self aligning bearings, keys, keyed rear axle, keyed sprocket and brake mounting collars, light weight steel rear hubs, spacers for rear brake plate, replacement inner cable and outer conduit all for £39.19.6.

The cost for the Mark IV Super Shrike upgrade increased to £44 because that version of the Super Shrike featured a glass-fibre seat. The kart featured in this article was identified as a 1963 Mark II Super Shrike powered by a Villiers 197cc motorcycle engine featuring a 4 speed gearbox. It was reported that when Buster Clarke was asked why he gave the kart the name Shrike he explained that the Shrike was a bird having a darting, swooping flight and that it collected and displayed trophies and that such a description seemed to fit a Class 1 kart that Motor Karts had designed. The Class 4 Super Shrike which is the subject of this article was almost identical to its Class 1 counterpart except for the longer wheelbase and the additional front wheel brakes Originally all the Super Shrike frames were unexpectedly made for Class 1 use because Motor Karts were perceived as being very much Class 4 orientated especially when their magazine advertisements were considered. A percentage of the frames were then cut behind the seat and lengthened by 2 inches for Class 4 use by slipping 4 number eight inches long ⅞ inch diameter tubes over the ¾ inch diameter main frame rails and then welded back together. At this time the Villiers engine was the main engine used in Class 4 racing and was centrally mounted behind the seat on the Super Shrike. Such an arrangement was known as the Mark 1 Super Shrike. 

The Mark II version of the Super Shrike mounted the engine behind the seat but offset to the left to help with cooling.  Because the space frame needed to be cut to allow the engine to be positioned to the left side the motor now became a stressed chassis member. At this juncture the Super Shrike frames were now made initially for Class 4 use and Class I versions  were constructed separately eliminating the cutting and welding process previously used during the Mark I Super Shrike fabrication process.
The space frame chassis was constructed using ¾ inch diameter 16 gauge ERW steel tubing. The steering hoop, seat back hoop and fuel tank carrier were fabricated from ⅝ inch diameter similar specification tubing. The chassis fabrication was interesting. The 90 degree bends in the main space frame were achieved by connecting the ¾ inch diameter tubes using a ⅝ inch diameter right angle bend inserted into the ends of the ¾ inch diameter tubing and brazed which must have been a very labour intensive practice. It certainly was one way of eliminating tube bender slip! 

Another interesting arrangement in the Super Shrike frame construction concerned the two longitudinal external trusses. The truss on the right side was taller by about ½ inch compared to the truss on the left side, which was the engine side. The variation showed when the kart was viewed from the rear; the cross members all noticeably sloped from left to right. The irregularity was probably associated with the positioning of the engine within the left side truss.
The front axle on the Super Shrike was fabricated from 1 inch diameter 6 gauge steel tubing. The axle was split in the middle so that each half could be replaced separately in case of incidents. The axle could be rotated using slotted holes to produce variable caster angles up to a maximum of 15 degrees. Although the Super Shrike featured in the article was fitted with a full circle 12 inch diameter steering wheel production models changed to an alloy butterfly type of yoke with wooden hand grips.

The seating position on the Super Shrike was extremely comfortable. The detachable 18 gauge aluminium seat which was suggested could be used to protect the engine when in the paddock from rain was thoughtfully angled upwards at the front to support the drivers thighs and to restrain forward movement under braking. The seat back, bottom and alloy sides were covered by one-piece of upholstery giving an internal seat width of 12 inches; 15 inches between frame rails. There was no continuous alloy floor; however an alloy foot well angled downwards from the front axle towards the pedals to support and keep the driver’s feet in position. The pedals were laid out conventionally. The brake pedal actuated all the brakes through a self compensating floating anchor plate to which were attached the three enclosed Bowden brake cables. The brake bios were adjusted on the anchor plate.

The small gear lever fell readily to the driver’s left hand and although minimal in appearance it was strong enough to resist the efforts of even the most ham-fisted drivers. The 1 inch diameter 60 ton steel rear axle was carried on self aligning 2 point fastening bearings bolted to ¼ inch thick alloy plate. The alloy plates on each side of the fame were attached to ¾ inch square section tubing welded to the top and bottom frame rails 5 inches apart. There was provision to have 3 bearings on the rear axle. However the kart in the photos featured only 2 rear axle bearings. The alloy plates on the engine side were spaced either side of the upright square section tubing using 1 inch long spacers made from 7/8 inch diameter alloy bar. The alloy plates not only carried the rear axle left side bearing but also had the rear engine carrying plates attached. At the front of the engine ¼ inch thick alloy plates attached the motor to a ¾ inch square section tube welded to the bottom chassis rail and to the stub of the top frame rail. This arrangement made for the engine to be a stressed frame member. Slotted holes in the front and rear engine plates allowed the chain tension to be adjusted.

Fuel was carried in a gravity fed alloy fuel tank 6 inches by 6 inches in cross section and 9 inches long. The tank which had a capacity of 1¼ gallons was carried by a tubular framed cradle attached to the back of the seat by two setscrews and to the rear upper cross member cum bumper by two jubilee clips. The tank which rested on thin rubber strips was held in place on the cradle using only bungee cords. Although many MB Wasps were supplied unpainted the Super Shrike was delivered finished in mid-blue cellulose with one piece black plastic covered foam rubber upholstery.
The Super Shrike could be adorned with Connolly steel wheels, Fastakart alloy wheels or the American magnesium Go Power wheels. The kart featured in the article was fitted with Fastakart fronts with 4 inch drum brakes and remoulded tyres. At the rear Connolly steel wheels fitted with 4.50 x 5 Avon slicks were used. A 6 inch diameter drum brake took care of the rear braking. The Super Shrike when fitted with the Villiers 9E/4 (cast iron barrel) weighed 176 lbs which was distributed in the ratio of 45% to the front and 55% to the rear. The wheelbase was measured at 47.5 inches, the front and rear treads were 33.5 inches and the height to the top of the seat back was 20 inches. The length of the kart was 60 inches overall.

At Motor Karts forethought and ingenuity were not obsolete in their Class 4 kart design. The Super Shrike achieved the distinction of being appreciably lighter than competing machines from other manufacturers and at the same time was stronger than most. The use of aluminium for parts such as engine mounting plates, steering drag links, seat, front floor and gear change rods contributed to the low all-up weight. However the greatest part of the weight saving was achieved by careful frame design eliminating all the non-essential tubing and the avoidance of chassis weakening multiple joints. Not only was the Super Shrike handling said to be excellent Motor Karts also proved that speed could be compatible with comfort; the distance from the seat back to the pedals was a generous 40 inches; their advertising literature in 1964 proclaimed that the Super Shrike IIB was the man’s kart for man-sized men with victory in mind, a statement that would not be political correct today! Considering the obvious care which was put into the fabrication of the Super Shrike, the kart at that time must have been one of the most obvious good value for money purchases available. 

It was reported that Motor Karts Limited struggled from time to time particularly from all the usual kart trade problems of getting fabrication jobs produced at a good price and in a reasonable time frame back then because the quantities involved were small and considered nuisance work. Such issues not only applied to their kart assembly but also to the production of their Merlin rotary valve engines. Nevertheless considering all the major karting models that Motor Karts Limited was involved with such as the original Wasp, the various Super Shrikes, the Buster kart which featured wooden sides, the Mini Shrike, the Snipe and the mark II version of that particular  kart which used rubber bushes on the rear end to provide a vibration free ride and ease of transport, the lay-down Slingshot, the Piranha, the Avanti and the Merlin rotary valve motors produced for both the 200cc class and the 250cc version it was amazing that such production was achieved with just seven members of staff, one of which was a bookkeeper. Above all Motor Karts Limited were renown for providing good quality and general excellence at a price that suited the karters’ budget at that time. 

In the autumn of 1968 Chris Merlin resigned his directorship at Motor Karts and left taking Tony Dowe with him to start up a new venture trading as Merlin Developments. Only months after Merlin departed from Motor Karts the pioneering British karting company sadly went into liquidation.

Press Release by: Vroomkart - 23/02/24

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