Gilson Excalibur Jr.

Columns: Legendary kart
The Gilson Brothers Company was a Plymouth, Wisconsin, based manufacturer of outdoor power equipment and recreational equipment. It operated independently between its founding in 1911 until acquisition by Lawn-Boy in 1988. Text: Frank Weir - Photos: Enzo Falconi Collection

In 1961 according to their advertising literature the Gilson Company was well known for being America’s largest producer of rotary tillers. The company also produced snow blowers and garden tractors.
Early in April 1961 Gilson Brothers, which was also their 50th year of being in business, manufactured a racing kart as well as a rental kart. The racing kart was marketed as the Excalibur Jr. and was said to have been designed totally for competition, built for rugged durability and was a perfect blend of grace and muscle. It was also reported to be sleek and lovely as well as being lusty eager for the track! Potential buyers were urged to drive one soon and experience the outstanding performance of what Gilson’s referred to as a superb racing kart.
The designer of the Gilson kart was Brooks Stevens. Stevens was an American industrial designer of home furnishings, appliances, cars and motorcycles as well as a graphic designer and stylist.

In 1961 karting was a fast growing field especially in America. Gilson’s decided on a new concept upon entering the fray. Their all aluminium riveted frame was not unlike the Rathmann Xterminator that was available at that time. The Excalibur Jr. weighed 90 lbs less engine(s). Sixty percent of the weight was distributed to the rear and forty to the front on a wheelbase of 40 inches .The front and rear treads were set at 30¾ inches. Six inch wheels were selected for the rear and five inch units at the front. The kart was delivered with 350 slicks all round.

The front axle was centre pivoted allowing 2 inches of vertical movement and was cushioned by rubber snubbers. There was evidence that at least 3 versions of the Excalibur Jr. rolled off the production line. One change involved swapping the front square tube axle to a round section. For smooth steering effect the stub axles ran in needle bearings.
Braking was achieved using dual external six inch diameter bands, 1⅛ inches wide, rod operated. 
Engine mount fastening to the chassis changed over the versions. Initially the mount fastened to the frame behind the seat. The swing mounts were cushioned on rubber to reduce vibrations. 

The engine compartment was formed by rolling aluminium sheet around the rear of the kart. Later the mount was bolted to the rear part of the chassis. To allow access to the engine bay the seat back hinged forward towards the steering wheel. Another development provided front and rear bumpers formed from alloy tubing and shaped very similar to the bumpers fitted to the Rathmann Xterminator at that time.
The kart also featured an adjustable steering wheel and a deep tuck and roll upholstered seat. The fuel tank was positioned under the steering shaft just ahead of the seat. Built in heel rests allowed easier foot control of the brake and throttle pedals.

The other kart that Gilson’s produced was a family fun/concession kart. That model was made with a ¾ inch diameter rear dead axle, universal engine mount, automatic clutch, austempered steel frame, king sized naugahyde covered upholstery, rubber floor mat, slick tyres, Timken tapered roller bearing wheels, self adjusting paddle brakes that pushed on the rear wheels, red bronze and white paint, chromed and dipped steering wheel. The kart looked extremely substantial and was said to have the stamina of a bulldog! The special feature that was prominent in the advertising was the double frame rails that kept the driver’s feet from sliding out onto the track. Heavy duty steel tubing was used throughout the fabrication and the kart was outfitted with nerfing bars to protect not on the driver but the brakes as well.  The chassis was actually made to carry a parent and a child, hence the use of a wide seat and the application of strong frame fabrication techniques.

As to the success of the Excalibur Jr. there were no magazine reports of the chassis having finished in the first three at a national event. However, there was photographic evidence of race successes at club level. Despite not making it to victory lane at a big meeting the Excalibur Jr. is still a highly sought after kart by vintage collectors.
Reading between the lines Stevens perhaps owned the designs and the name but had Gilson’s undertake the manufacturing and sales of both the sprint kart and the rental version on his behalf.  
As to Brooks Stevens, sometime in 1965 he designed two karts specifically for the enduro scene which were known as Excalibur Jr. Formula Kart Experimental machines.

One of the Excalibur FKE karts was fabricated by a gentleman called Ray Besasie Sr.  who made the bodies on a number of Stevens’ race cars. Only two FKE karts were made for Stevens, one of which started out as a King kart and was modified by Ray Besasie Sr. for racing on sports car circuits. The other which was also known as an Excalibur Jr. FKE was a totally new design from Stevens’ drawing board and was made by Ray Besasie Jr. when he was just 17 years of age; his father must have taught him well. 
Both FKE karts were on display at the Stevens’ Museum until its closing in 1995 at which time they were sold to a collector in Texas. The King kart derived chassis ended up in Harm Schuurman’s karting museum in Holland and the Excalibur Jr. FKE kart remained in America and is currently part of the Dan Flanders Collection. 

The Excalibur Jr. FKE kart was powered by twin West Bend 820 motors (8.2 cu in/135cc). Each engine was fitted with dual carburettors ported to run on methanol. The motors each produced about 20-25 HP which gave the kart a top sped of approximately 130 mph. The collection tanks under the steering column and behind the seat prevented the motors from suffering fuel starvation under braking and on banked turns. The tanks were hand formed from aluminium and welded using oxyacetylene, a technique that was developed in the aircraft industry. The oxyacetylene annealed the aluminium and stopped the weld from becoming too brittle, an outcome that would have happened if welded using MIG or TIG processes.
Upon his death in 1995, aged 83, the New York Times called Stevens 'a major force in industrial design'; his Excalibur Jr. karts were certainly different from main stream in the sixties whether sprint or FKE.


Created by: cggiuliano - 22/03/24

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