recently a buddy of mine gave me a 1974 Honda xl100. its my first bike Ive ever had. he got it for free and worked on it till it started to run. the problem im having is that ever 20-30 mins of riding the bike will start to sputter then die. its because the spark plug gets too dirty and I have to clean it off. I plan on taking the bike apart once it gets cold outside and work on it but in the mean time I would like to ride it. so my question is: is there any quick fix just to help it run longer or do I have to take the carburetor apart? any advice will help thanks!