When I was looking for oil I read that Rotella had been dropping their zinc/phos levels every year for the past few years but it's still up there at around 1200ppm if it's branded Rotella T. Otherwise racing and the high mileage oils have more ppm zinc/phos levels. If you want very high levels you may have to special order the racing types which can have upwards of 2300ppm zinc/phos or high mileage avg around 1200ppm.
The standard ppm off the shelf is going to be anywhere between 750ppm to 1000 and getting less and less every year due to clean air requirements etc. Here's a sample ppm/additive etc. run down of Mobil1.
http://www.mobiloil.com/USA-English/...duct_Guide.pdf it's the only one I could really find a detailed info sheet on in one place.
The worst thing for wet clutches are friction modifier additives that many oils have, so far the Rotella has stayed away from those, if not ordering the kind Kart suggests, then going with the Rotella as the back up as Spokes suggests is the best option.(Kicking over the motor in gear, with the clutch lever pulled in, with the key off also helps break free stuck clutch plates, it also breaks free any after a few weeks of sitting.) P.S. make sure you're pulling the clutch and not the front brake...yes I've done that
