The Bultaco Model 159 was built for Trials competition.
Bultaco M159 
M159 M91 M49 
Perhaps the most famous Bultaco model is the Sherpa T, a trials bike, which revolutionised the sport in the 1960s. At that time trials was almost exclusively a British sport using big heavy four-stroke machines. Irish trials ace Sammy Miller teamed with Bultó to produce a lightweight two-stroke machine. Overnight, the Sherpa T rendered the heavy four-strokes obsolete. Miller won the gruelling Scottish Six Days Trial in 1965, and then repeated the feat with wins in 1967 and 1968. He also claimed the European Trials Championship in 1968 and 1970. This coincided with the growth in the popularity of trials in Europe and later the USA.
The popularity of trials provided a lucrative market for Bultaco in the years to come. Bultaco dominated the World Trials Championship in the 1970s, winning the title eight times, and winning the Scottish Six Days Trial four times. Sherpa T is a reference to Tenzing Norgay, Sir Edmund Hillary‘s indefatigueable climbing companion during his famous first ascent of Mount Everest.