Brian, your the first I've read about having a problem with the cam chain tensioner on a 2014/15. I was wondering if I should go with Rally Raids tensioner. They seem to be the only one making a mechanical one for the 690.
I haven't checked the manual, are you say the bike requires mineral oil in the tensioner. I thought it was fed oil from the engine? Or are you talking about a petroleum based engine oil instead of a synthetic?