I have a 75 sohc engine. I changed the front sprocket to run a 530 chain. What was on the original bike was a sprocket without bolt holes, a backing plate with bolt holes and a retaining c-clamp washer. I bought the new sprocket and it fits great. the new sprocket has bolt holes. However, now the backing plate with bolt holes does not align with my new sprocket. What gives?? do I need to find a new backing plate...I am confused...thanks guys.