Thanks for the tip. I have already got my hands on a PRV V6 from a 604 which i am currently considering to rebuild or not. But i have 3 KF pumps, and i wont get peace of mind before i get one of them to work properly...If you can't get the KF running properly, you should consider twin 40 mm DCOE's (DCOE manifolds are hard to find, but available) or a Weber DGAV on an Argentinean manifold and an electric fuel pump like a Facet.. Not quite as smooth, but very reliable and far less temperamental. It has been my experience that the KF system can run forever, once. Once you open it, it's game over. You can send it to hermann.sattelberger@de.bosch.com. for a professional rebuild, but then the fuel pump tends to crap the bed when sitting long. So the carburetors provide peace of mind for a long time.