I take the simple approach where the primary is concerned - take my bike to my local friendly indy. Takes him moments compared with me! Just an option.

 

Local Indy won't touch anything 10years or older. Plus my bike is like my woman I'd rather not let another man fondle her lol

 

Did you check all the connections from the battery to the starter?

Often those main line connections look good but they still need to be taken apart, cleaned and re-tightened back on. Corroded or loose connections are a known issue and the easiest to fix on your own.

Many have solved this problem at no cost at all by checking those connections.

 

I didn't take time to watch these vids, but should give some insight.
Click on the Youtube title at top of video.