He entered the 250cc class too , to get more practice time on unfamiliar tracks .
Kenny Roberts made his full - time GP debut in 1978 , wanting to win the 500cc championship at his first attempt .
Kenny Roberts entered the 250cc class too , to get more practice time on unfamiliar tracks .
Kenny Roberts made his full - time GP debut in 1978 , wanting to win the 500cc championship at his first attempt .