I know there are probably a bunch of threads about oil but im starting another one . When I first changed the fluids in the 85-86 motor the clutch was grabbing great , after a few test rides i changed it again to clean out any gunk from the previous owners lack of maintenance . First change i used Castrol 2 stroke crank case oil but for the second i only had regular motor oil laying aroung (Mobile 15w40 i believe ) now im getting clutch slip at the top of 4th and 5th gear . I know the new oils have frction modifiers (not good) I only ran it for 15-20 mins with the Mobile oil in it , the question is could I have burned up the plates that quick or will the clutch grab if i put the 2 stroke crank case oil back in it after a long warm drain out ? Also any other suggestions on crank case oils would be appreciated I dont have any Atv or bike dealers near me so I like things I can find at Pepboys , auto zone or walmart . As always thanks in advance for any help and info !!!Winkdogg . PS I PUT A LINK IN MY OTHER THREAD WITH PICS OF SOME OF MY QUADRACERS !! JUST CLICK THE LINK TO TAKE A LOOK!