I bought my '02 919 last fall. Guy dragged it out of his shed. "Never been dropped" Rrriiiigggghhhht!!! Changed all fluids. New air filter. The dead mice in the old one were problematic I think. Replaced all plugs. It has a PowerCommander 3 which I downloaded and installed the correct map for an '02 919 with a full 2 brothers exhaust. Runs fine for the first half hour then sputters, and stutters. Seems to get worse as the tank gets emptier. From reading other threads on this forum, I have decided it's the fuel pressure regulator. That is now on order. My question is should I drain the tank as much as possible when I replace the fpr, or just replace the fpr and see if that takes care of all the issues?