As a matter of interest Yeti NONE of my bikes leak oil-the old Gilera is a unit construction engine which they described as an 'hermetic' engine. Basically if you take it apart the mating faces on the cases are about .75" which is about 3 times as wide as comparable British bikes-ergo it doesn't leak. Mind you it isn't very fast either, revs to about 5,000-which is what the TZ 'ticks over' at...........
John
[Edited on 4-10-2004 by Monty]