I have a 1975 xs650b that starts on one kick, idles well, and runs great through all of the gears. I have stock airboxes and standard carb settings. I ride it every day to work but my commute is 1 to 2 miles tops. I let it warm in the morning before I tear off- I feel like I go through too much gas. It's hard to gauge mpg because my commute is so short and it is always stop and go around here. Now the dumb question- If gas was somehow leaking down past the pistons (due to some undiscovered carb problem) while riding, could the bike still run so well? My plugs look great and I don't notice an increase in my oil level. Maybe the bike is just running too well now and I'm paranoid the engine is going to blow up. Thank you all for this great site-