Clutch Slipping or worse?

Stay with Shell Rotella oil and zinc is still there. I get the oil analysis done on the goldwing and my diesel truck and can directly compare the new SM formulation with the older formula for the last 10yrs or so and zinc in the SM rotella is more or less equal to the older. I'd go out on a limb and say any 15w40 made is fine on zinc so I think the zinc scare is kind of over exagerated.
Look at Bob is the oil guy forums for oil reports on different brands of oil, different engines and new virgin oil. It looks to me like most oil is more or less the same, so if it's oil it will do it's job just fine regardless of brand really. Stay away from energy conserving oil supposedly, but I've even used it and had no problems. Used STP before too and no problems. Never adjusted the clutch either other than cable free play and no problems. Clutch is not rocket science on a motorcycle.

Make the adjustments, then if you don't have a recently rebuilt engine: take the cluth cover off and calean the plates, you might be surprized what's on there. Mine did the slip thing for a long time. It wouldn't hook up until I drove the bike for at least 10 miles. Turned out the plates were covered with a layer of slime. Carb cleaner and a rag and even if they are worn some they'll grab like new. Most bikes Iv'e worked on and owned always needed more than 1/8 of play to keep the cable slack and the clutch from slipping

I've been out of town for the past few days, but thank you for all the responses. The weather here has been beautiful for riding so i hate to tear down the clutch to check it, but I will if I have to.