One should never switch to synthetic oil during the life a of a mototr that
has been living on non synthetic. The reason behind this is (from my
understanding) oils do have some natural deposits in them, kinda like home
brew beer. these deposits make microscopic grooves in the metal and they also
build up over time in the motor creating a film. This film is what keeps your
compression good and your oil in the motor, the build up around the seals is
essential. So when you go throwing perfectly brewed synthetic oil with
detergents in it it breaks down the deposits and thus you will spring leaks
and comprimise the integrity of your motor.

Sooo always drink unfiltered beer and stick with castrol 20w-50....

stay away from bud

Chris
VT
91 westy (no leaks 157k)

PS this also goes for trannies and front diffs....