This may sound a little odd, but what oil filter are you using? I know that the people here recommend a variety of different filters, but you really should use a filter made for your bike. A filter will provide back pressure which will help maintain a certain amount of oil in the upper end of the motor. This information came from a Triumph mechanic I knew some years ago. I've been using the Hiflofiltro # HF 191 with good luck so far. Just a suggestion...
