Yeah, I know how you feel. I have to smog mine in June!! Unfortunatly I removed all my smog equipment waiting for the 30 year rolling exemption. Then the Governator took over and I have to smog my 02 after all. What a bitch. Here is a diagram I believe is from a '76. I've been told to replace the EGR valve and get an electronic ignition if you haven't already. New plugs would be good to. There are also fuel treatments they sell that can help clean your engines internals before a smog test. Hope this helps!!!
http://www.bmw2002faq.com/component/option,com_forum/Itemid,0/page,download/id,16930/
EDIT!!! Try this stuff. It just might work!
http://www.partsamerica.com/ProductDetail.aspx?MfrCode=CRC&MfrPartNumber=05063&CategoryCode=3233