I have two problems that I need help with. My engine is stuttering at 1/8 to 1/4 throttle and I'm burning a little oil. Any help with each problem or a combination fix? The engine stuttering, I thought was a jetting issue when I went on an out-of-town ride, but now the bike is at home and I still have the problem. At higher throttle, everything sounds and feels fine. After this weekend's race, I noticed some black soot around the exhaust. I have the JD Jet kit and jetted to the recommendations. Today, I played with the fuel screw and the bike still ran with it turned all the way in. I changed the air filter and had the same results. The bike used to run fine and I didn’t make any changes. While I hovered over the bike this afternoon scratching my head, I checked the oil on the dipstick. It was low so I filled it back up to the right level. I needed to add 200 milliliters. I have about 7 hours of riding since the last oil change. Do I have a problem or problems? What do I need to do?