Complex sentence: The Lightweight class of the 1920 Junior TT race was won by Ronald Clarke riding a Levis and he may have won the event overall but crashed at the 33rd Milestone on the last lap, finishing fourth overall.
Split into simpler sentences: The Lightweight class of the 1920 Junior TT race was won by Ronald Clarke riding a Levis. He might have won the event overall, but crashed at the 33rd Milestone on the last lap, finishing fourth overall.