http://www.nortonownersclub.org/history ... 954-trials
350 / 500 TRIALS
For the never implemented range for 1940 Norton had intended to offer a single trials model with either 348 or 490 ohv engines. It was to be based on the rigid ES2 frame and it is surmised that the three ES2 machines used by the Army in the 1939 ISDT were prototypes. The 'works' bikes built during 1945 followed this approach, had a short wheelbase rigid cradle frame, International type rear tank lug, Inter girder forks, WD adjustable handlebar clamps, WD rubber bump stops, some had the Manx 8" cone front brake and 21 x 3 and 18 x 4 inch Universal tyres. The petrol tank held just over 2 gallons and the engine was based on the standard Model 18 motor, but was fitted with an alloy Inter barrel and the alloy head developed for the 1938/39 bikes. Ignition was by either BTH or Lucas racing magnetos. A high level exhaust system with a 1937 type silencer was fitted. The gearbox had wide ratios and a folding kickstarter. The 350 used an 18 tooth engine sprocket, whilst the 500 had a 20 tooth sprocket. Racing clutch and brake levers, reinforced steel mudguards, short footrest hangers with the tubular footrests adopted from the WD machines completed the ensemble. The 350 utilised the 500 crankcase, but mainshafts were 25mm dia. as prewar. For the 1947 season these bikes were fitted with teles and the frame was extensively modified. The front down tube was shortened by 1.5" and some curious bends incorporated in the front down tube and tank rail to provide a more upright steering head.
At present six bikes are known to survive, the Billy Matthew's D30T in Canada, three 500s (1 No. A3T and 2No. B3T) and two 350 (Bl3T), one being Ted Breffitt's machine.
500T
A return to the open frame Model 18s used in the immediate pre-war years was the basis for Rex McCandless's reworking of a WD 16H, with a short wheel base and fitted with reinforced alloy mudguards. the alloy version of Norton's 1938/47 engine was retained. The fork yokes were revised to bring the fork stanchions nearly parallel with the steering head and a light gauge steel petrol tank with single bolt attachment provided a unique feature. originally painted in the manner of a Manx tank, production machines had a dull plated finish. Massive steel footrests attached to the bottom of the alloy engine plates had been the work of Terry Hill. A low level exhaust system ran the pipe under the engine timing cover. The front brake had a 5-1/2" drum, but when production models appeared, they had the road bikes 7" drum, extensively lightened and fitted with an alloy brake plate. An alloy version of the redesigned 1948 engine was in use on factory and production bikes by the year's end. Standard gearing was 5.6; 8.3; 13.15; 18;5. A BTH KD1 magneto provided the sparks.
After its debut, the production model received very little development. Chrome shortages saw paint finishes on tanks and rims. The gearbox end cover was modified to make it easier to change the kickstarter spring and the Wellworthy Company produced head and barrel using their patent AI-Fin system, which had originally been developed for aircraft engines. An 8" front brake was fitted in 1954. Other companies continued to improve their machines and 1954 was to be the last year when rigid framed trials machines were campaigned by the major factories. AMC were on the point of introducing their own sprung trials machines and saw no point in Norton taking a slice of the market.
Twenty five 1954 models were built, these terminated the production run which between 1947 and 1953 had seen a total build of some 850 machines. It is thought that nearly 200 still survive.
Also
http://www.bonhams.com/auctions/18294/lot/221/
1952 Norton 500 Trials
Registration no. ANC 707A
Frame no. G443714
Engine no. B3T 13350
Norton's post-WW2 trials campaign got off to a false start in 1947 but after a season of extensive modification and experimentation the factory came up with the legendary 500T. Shortened rear frame stays and a modified lower fork yoke reduced the wheelbase to a more-manageable 53" while an alloy cylinder head and barrel helped reduce weight to around 300lbs. Numerous works and privateer successes soon confirmed that Norton had produced a machine as good as, if not better than, any other rigid-framed trials iron.
Offered without reserve, this collection of parts represents the basis of a highly desirable classic trails bike. It consists of a Norton 16H frame modified to 500T specification; a 500T engine; a 'doll's head' gearbox; long Roadholder front forks; a fuel tank; alloy engine plates; a front brake back-plate; a rear stand; two new Dunlop Trials Universal tyres; and a box of miscellaneous parts. There is a Swansea V5C registration document with this Lot.
Sold for £2,300 inc. premium