Husqvarna became a very popular choice in the United States for motocross and desert racing; and by 1970 the 4-speed models were some of the best ever made. However. when Husqvarna introduced the 5-speed models in 1972. the new bikes were heavier and the performance suffered. Many riders did not like the 1972-1973 bikes as much as the previous ones. The factory listened. and these complaints were resolved in 1974 when Husqvarna introduced the all new "Mag" model. Extensive use of magnesiuim (in place of aluminum) resulted in a much lighter racing machine. In addition. the introduction of the new "reed valve" induction really woke up the performance of the engine. The results were spectacular. Today. some people believe that the '74 MAG was one of the best Husqvarnas ever built. The bike continues to be an extremely popular choice of vintage racers and collectors alike. This bike run great I have owned it for eight years the stock pipe and head is included in the sale.