FInally today I got to the job of installing a new mechanical tensioner that I had purchased before the summer. I printed out the instructions from the DVD and it took me about 5 hours, including replacing one of the 2 idle actuator air hoses (I think that is what they are called, as a "when you are in there" job. The hose had indeed split at the connection to the intake, enough to let in air where it was not supposed to be. The other hose looked in good shape but, just for good measure, I trimmed off the end and reconnected the 'fresh' end.
The only part of installing the new tensioner I wasn't sure about, since it is not clearly covered in the workshop manual instructions, is how to remove the 'pin' that keeps the tensioner retracted, once the device is in place. It turned out to be simple enough - with a pair of pliers I put upward pressure on the pin and -click!- the pin came out easily and I could hear and feel the tensioner 'spring into action', literally. The old tensioner was extended to a degree, and was immovable at that length - absolutely no spring action, it could not be pressed in nor extended longer. By design I believe they are supposed to exert some light pressure on the chain guide or whatever is down there, but the old one was just 'frozen'. Started the bike up and - runs great again, no more death rattle. It had started rattling about 1,500 miles ago and I was constantly worried that the engine would grenade. Hopefully this third merchanical tensioner (in little over 10K miles) will last a bit. Once it starts being noisy again I will probably bite the bullet and convert to hydraulic - although it does not look like a fun job. Most of my 5 hours today was prying off all the fairings and putting it back on (I had to take off both sides to get at the idle air actuator hoses, otherwise it would have probably been about an hour and a half less).