Well, got the gas tank all cleaned out and relatively rust free now. New fuel line, new fuel filter. Cleaned out the carb and installed some new o-rings. Still has the same problem as it did when I brought it home, it will start right up and run fine when cold. Sometimes it acts like it runs lean (rpm's take off on their own) and sometimes it wants to run rich (when returning to idle it just dies unless you twist the throttle a little bit). I've double checked the cables. The slide isn't hanging up. I do seem to have a different carburetor then what may have come with the bike. I have another hookup next to my fuel line inlet that when you open the slide a little bit you can blow air in but if you close the slide it blocks it off. It would seem like it's for a fuel pump setup or something. Is there an aftermarket replacement carb. for this bike or another carb. from a similar sized yamaha engine that may work? It looks like the previous owner really jacked this carb. up. Thanks in advance.