Some experience with my BMW R1150R has raised some questions about oil consumption rates. I purchased this bike with about 8,000 miles on the odometer. I refilled it with re-filled with Redline 10w40 at about 10K, After a lowside (crash) spilled a lot of my engine oil. 10w40 is slightly lighter than OEM spec, but was recommended for winter riding. In the next 4,000 miles of riding, the BMW consumed nearly 2 quarts of oil. At 14,000 miles, I refilled with Amsoil Moto 20w50, and I now have 17,500 miles on the odometer. In 3,500 miles of riding, I've only added a 1/4th of a quart. The bike is still showing a healthy oil level through the inspection window. What might cause my oil consumption rates to drop so significantly after switching oil brands? I doubt that the oil weight difference accounts for all of it. Are Ester based oils known for greater consumption rates? Is Amsoil particularly stable? What other brands are known for low consumption rates? I'm tempted to refill with Redline 20w50 at my next oil change in order to get a real comparison. For anyone unfamiliar with this bike, the BMW R1150R is an opposed cylinder air/oil cooled twin. I have BMW riding friends who are also interested in lowering their oil consumption levels; it's not uncommon for these bikes to burn through a half a liter of oil every 1000KM.