Originally Posted by acousticrawk
Guy I work with runs straight 40w in the forks if his 55 Indian and swears by it.
Maybe the fork damping design
calls for 40w (probably more correctly "SAE 40”)?
of the 80s and 90s BMW forks with which I am accustom calls for telescopic fork oil ESSO Komfort, i.e. SAE 10, or Esso Super Komfort, i.e. SAE 7.5, below 50 deg. F.