Get yourself a Haynens workshop manual for the 528i-530i 75 to 80 E12.It has 4 pages on the Zenith carburettors.Good luck,Fred I'm looking for a diagram (e.g. exploded view) or detailed service description of Zenith carbs. Ideally something alnong the lines of the Webber diagrams at www.piercemanifolds.com or www.theape.com. Any leads would be greatly appreciated. I'm trying to cure a rough cold start on my '72 CS.