Complex sentence: Speedway racing was staged at the Athletic Grounds, Rochdale in 1928--1930 and returned at the start of the 1970s when it provided a home for the British League Division Two Belle Vue Aces juniors and Rochdale Hornets.
Split into simpler sentences: Speedway racing was staged at the Athletic Grounds, Rochdale in the pioneer days of 1928--1930 and returned for a short spell at the start of the 1970s. The 1970s venture provided a home for the British League Division Two Belle Vue Aces juniors and the team was known as Rochdale Hornets.