My bike started using about 1 qt. every 1000 miles right after my engine casing had to be replaced. It seemed to be the worst on continued highway travel. I made a couple of changes that cut consumption to about 1 qt. every 4000-5000 miles.
I started running the oil level at the bottom of the indicator (Triumph's suggestion). I also noticed that my breather hose had a slight dip in it. You do not want any way oil can collect in the hose. Oil that would normally run back down into the crankcase can collect and "burp" into the airbox. I cut about an 1" off the airbox end of the hose and reattached. These two steps did make a big difference.
Triumph did make a change from my original model which had a rotary breather. The newer crankcase (like I have now) is slightly larger on the breather side and has a different type of breather. Still, it seems like some sort of design flaw.
