Originally Posted by jscottyk
Thanks for the clarification. I think what is confusing me is hose #2 is shown on this diagram
is listed as the crankcase breather. This is probably a semantics thing resulting from the German->English translation.
So, it looks like the #2 vents gases straight to the bottom of the airbox, while #4 goes through some sort of solenoid valve after first passing through a set of reed-valves in the cover (#5).
They seem to both be crankcase breathers in some way. #2 is the crankcase breather hose if that is what is listed in the service manual. #4 might be some sort of supplement to the system??