Just got a 1975 Cb 360 with just over 11,000 miles. He said that he just had the carbs rebuilt not long ago but that it burned a little oil in the left hand cylinder. Picked it up (gave $700) started to drive it back and when i stoped at a gas station about 30 miles down the road i relized it had a problem when i went to start it back up i noticed that it was leaking gas out of the left muffler. anyway long story short took 7 gallons to get back then noticed gas in oil couldnt get the rmps up over 5,500 with out downshifting down a hill . its my first bike and any help would be great