So there I was, out for my last ride of the season today. Actually going to the bike shop to pick up some gasoline stabilizer, change the oil & put it away today. Ten miles from home, sitting at a red light in neutral and all of a sudden, a loud mechanical "whirring" noise coming from the engine. At first I thought it was a truck's engine brake pulling up behind me. Scared the shit out of me as I looked in the mirrors. But it was me. It increases frequency slightly as the engine revs, also. I got it home and it ran just fine, although I never reved it up beyond the minimum to get it home. It's a '97 with 25,000 miles. I haven't changed the cam chain tensioner yet. Being non mechanically inclined (bike wise) that's the only thing I can think of.
Any suggestions????