My 82 CM450E hasn´t started without bump starting since spring. It was starting intermittently when I´d charge it overnight first or when I was lucky, but now all it does is clicking coming from the solenoid when I press the start button. I checked the start button and switch and even swapped out the solenoid. Does anybody know what I should check next? What does the CDI do? How do starters wear out on these? Should I rebuild it?