I know the topic of oil has been discussed to death, but I still could not find an answer to my question. On my last oil change several hundred miles ago I put in motorcycle specific synthetic 5w-40. My mpg's are up slightly and the butt dyno thinks there is slightly better acceleration. Plus I have easier shifts (like downshifting from 2nd to 1st). Is this lower viscosity oil going to cause any problems in the DR? I don't seem to be burning any. My thoughts are that when Suzuki first designed this motor, this oil didn't exist, so the factory recommended 10w-40 might not be that critical. Any thoughts??