50cc Roadracing 1963







1963


Kreidler


In 1963 the kreidler racers got a new frame, with the tubes now under the engine, while the engine itself was the same as the 1962 version, with detail changes to improve the power. The swing-arm front forks were replaced with telescopic ones. Front brake now double-sided sls. No horsepower figure was given, only that the engine speed was over 11,000 rpm.

Suzuki


In 1963, the RM62 was succeeded by the RM63, which was changed in a number of details. Compression ratio was lowered to 8.8 : 1, and the engine pushed out 11 bhp at 13,000 rpm. 9-speed gearbox. In MZ fashion the exhaust pipe was connected to the back side of the cylinder. For better cooling, the dry clutch sticks out from the fairing. Top speed 150 km/h. Hugh Anderson won the title, second was Anscheidt on Kreidler and third Ernst Degner on Suzuki.

Honda


During 1963, Honda did not participate in the 50 cc class, except for the last race of the season, the Japanese GP, where the RC113 made its debut (see under 1964), and the only Hondas appearing otherwise were in the hands of private riders on CR110 production racers.



Derbi


The only thing known about the Derbis is, that the engines now had water cooling and rotating inlets and eight-speed gearboxes. Derbi4: Busquets during the French GP, where he finished fourth. Pic. Derbi6 shows the arrangement of the electronic rev. counter and the temperature gauge. The indication pointers for the revs to be used and the maximum of 8000 rpm on the scale of the counter point to the fact that the rev. counter indicated 1 : 2!

Tomos


Tomos stopped participating during 1963 and would not return to GP racing until 1969

Tohatsu


Another Japanese entry in the 50 cc class was the Tohatsu. It was first introduced during the 1962 Tokyo show (which was held in November 1962) and didn't look very professional then (see Tohatsu1). Nothing much was known about the bike, except that it was a single cylinder two-stroke. During 1963 the bike re-appeared, this time as a twin-cylinder two-stroke, with a top engine speed of 16,000 rpm! This proved to be a very interesting little bike, which was beautifully engineered, see Tohatsu2, 3, 4, and 5. The cylinders were cast in cast-iron. Bore and stroke were 31 x 33 mm for 49.9 cc - a long-stroke engine, very unusual at this point in time to say the least! Carburettors Dell'Orto (also surprising for a Japanese machine) with a diameter of 16 mm. The inlet worked with a normal piston controlled port, no rotating discs. Power output was 10.5 bhp at 14,000rpm. At the right hand side of the engine an outside oil pump was mounted, which also housed the rev. counter drive. What I wrote previously about the HMW cylinders also held for the Tohatsu: the transfer ports had little covers (see Tohatsu3), making it easy to work on them. The crankshaft had needle roller bearings for the big- and small ends, the con rods were knife shaped. Ignition was by battery and coils and, of course, two sets of breaker points. Primary drive was with gears to the six-speed gearbox. Gear ratios were 2.265 - 1.778 - 1.500 - 1.333 - 1.173 - 1.042 : 1. As can be seen from the pictures, the frame was a double tube frame, with hydraulically damped telescopic front forks and -swingarm rear. Front tyre 2.00 - 18, rear 2.25 - 18, front brake double sls. Total weight of the bike was 56.5 kg.

The Outsiders



MZ


For 1963 the 50 cc MZ got a water cooled cylinder, while retaining the air-cooled head. The carburettor now had a remote Dell'Orto float chamber. Alas, mainly because of political problems (the factory often did not get visas to take the bikes beyond the iron curtain), the development was stopped during 1963.










Listen !
Enjoy the filmage of the Suzuki race- team touring Europe:
Part 1: http://www.youtube.com/watch?v=3yMg-f-T5QI
Part 2: http://www.youtube.com/watch?v=zufKezfvN7Y