50cc Roadracing 1968



For the races during 1968 the RK67 was used, but, probably worried by the rumours of a Honda three-cylinder 50 cc, Suzuki developed their own triple. See pic RP68-1. No photo of the complete bike has ever been made available, this is a drawing. It was a water cooled engine, with one cylinder vertical, and two cylinders pointing forward under approximately 100 degrees. The bore was 28 mm, but various sources are not clear about the stroke, which is given as 25, 26.5 and 27 mm, which would result in resp. 46.18, 48.95 or 49.88 cc. The latter seems the most probable, although an authoritative Japanese source mentions the 25 mm. Contrary to the twins, the triple had monoblock Mikuni carburettors instead of the ones with remote float chambers. Power output was 19 bhp at 20,000 rpm - the power band was only 500 rpm, reason enough for the 14 speed gearbox! Top speed was given as 200 km/h. Pics RP68-2, -3 and 4 show the engine in detail. The water pump is situated next to the vertical cylinder, the oil pump with its bunch of spaghetti sits behind the vertical cylinder. A pity we were never able to see, and especially hear, this screaming little bike!


Derbi was the only other works participation. No details of the bikes are known.


For 1968 the Jamathi got water cooling, and a completely new engine, retaining the nine-speed gearbox (see pics. Jamathi 4, 5 and 6. The bike was now so fast, that during the Dutch TT Paul Lodewijkx not only made the fastest lap, but also managed to beat world champion Anscheidt on the Suzuki twin into second place! A week later, on the super fast Franchorchamps circuit, he couldn't repeat the feat, but his second place behind Anscheidt was very creditible. (see pic. Jamathi1).