THis is a Euro 930, I don't think it HAS an oxygen sensor, does it? Definitely no air pump... Mechanical injection here...
Now, you're saying lean it out untill just before it runs rough? I was told to increase the mixture richness untill the idle doesn't climb any, then back it off slightly.. AUGH..
Well I made an appointment to a guy with a tester... I'll have him set it once for emmissions, then set it back for smooth running, they're definitely NOT the same setting