Kart Engine 125 M5
Bultaco introduced special versions of their engines for Kart Racing in 1962 with a full blown effort of three engines, the K100, K125 and K200. The kart engines clearly followed standard Bultaco design practice, making full use of existing parts and design work, although only the larger models were straight copies of their motorcycle engines and the smallest engine was specially manufactured with kart racing in mind.
The K100 had a capacity of 99.10cc, 4.95 x 51.5 mm bore and stroke, 14:1 compression ratio and produced 13.5 bhp. Weight of this engine unit complete with carburettor was 16 kg. The K125 was essentially a TSS racing engine, but with an Amal Monobloc carburettor and air filter. Although everything else was the same, power was down by 1bhp to 19bhp. Fully equiped, this engine weighed 23 kg. The K200 was largely the Sherpa S200 engine, complete with the dirt model’s carburettor and exhaust, so its power output was an identical 24 bhp and weighed 24kg.
Proof of the success of the Bultaco engines was provided by the fact that they remained a popular choice of kart racers right up to the seventies.