Just another random suggestion. I know you believe it to be coming from inside the engine. I had a noise once that I thought was two because sometimes it would be a random clicking and sometimes I has a metallic buzzing sound. I had lost the rubber bumper off the kickstand and it was clicking and buzzing against the primary. Hope you find the gremlin and that it's an easy inexpensive fix.

 

Thank you. Will look at both suggestions.

 

Follow up time for those of you who participated last fall. I hate it when someone asks a question, gets answers and never follows up to tell us who was correct.
I tore it down a few weeks ago and found the front rod bearing is bad. This crankshaft was rebuilt by Darkhorse 5 years ago and only went 40,000 miles before giving up again. I haven't sent it back to them yet but they sound like they will make things right.
Anyhow thank you to all who contributed last fall.

 

Thanks for the follow up! Like you it can be very informative when the finale outcome is known.