Complex sentence: When The Wailers parted company with Perry in 1971 taking The Upsetter's rhythm section with them, Adams remained with Perry but by then had begun to split his time between Jamaica and the United States.
Split into simpler sentences: When The Wailers parted company with Perry in 1971 taking The Upsetter's rhythm section with them, Adams remained with Perry. During this period Adams had started to split his time between Jamaica and the United States.