I have hours and hours on my slipper clutch and haven't oiled or anything with no problems, pretty much maintenance free. One thing I would suggest is to take off the outer spur/pinion cover and see if the the clutch bell is turning while it 'slips'. If it isn't turning it is definitely the clutch not the slipper clutch. I have had no luck with running the stock LST2 clutch for very long with the clutches staying intact. If it is the clutch, a bullet proof clutch is the Fioroni Turbo sliding clutch. It is a little expensive, but it absolutely rock solid!!!! I usually got one weekend on the stock shoes before they were shot, but I got a whole summer with the Fioroni clutch and it's still running strong!!!

You may have to shim the motor up about 1.5 - 2.0mm and flip one of the slipper clutch gears to align the gears properly with the spur gear and possibly use athe Dremel on the top deck for clutch bell clearance, but the trouble will be worth it (I had to do this with the TiNi gears).

As was mentioned, LSTFORUMS.COM has a lot of info on the Fioroni conversion along with a TON of other useful info. One other LST2 tip....
MUGGIFIED LST2!!!!

Gerber