I have a 1983 R80 rt which seems to be suffering from fuel starvation, there have been some odd electrical problems (since solved) which have muddied the waters a bit.... The bike runs well on a full tank of fuel but as soon as I switch to reserve (main "tank" empty) it splutters and struggles, only running well with full choke. Sounds like fuel starvation to me? If I loosen a fuel line (tried this on both sides) there is a steady flow of fuel out of the taps with the petcocks in the reserve position. Loosening the tank filler makes no difference either so there is no vaccum locking occuring that I can tell. A couple of months ago I overhauled the carbs with new seals and jets and, as stated earlier, it runs well on the main tank setting of the fuel petcocks. The problem occurs as soon as the reserve setting is chosen. Before I dismantle the petcocks (again, all was cleaned 12 months ago) and carbs in a wild hunt (for what?) does anyone have any suggestions?