Motorcycle Repair: 1979 kawasaki KZ650D, gas tank, brownish color

Question
i bought the bike  ,it ran great  for a week but now it tends to bog out as i twist the throttle and just loses power d.. i let it sit then it works again.it isnt fuel injected so it isnt a fuel pump problem  now its having issues starting. i looked into the gas tank and found rust. i m in the process of cleaning the gas tank. i know rust got into my bike because i drained the gas and it was a brownish color with some rust particles in it and i was riding it without the knowledge of rust.  how would i go about cleaning  out the rust/bad gas?

Answer
Adam this probable a sign that the bike sat for a while. Try a gas tank prep product called (Kreem) it has 3 bottle and is about 39.00. One bottle uses acid to etch and clean the inside of the tank. The next bottle uses an acid nutrilizer.Make sure the petcock is out of the tank.The third bottle has a white glue like coating that is poured into the tank and coats it if you have any leaks.Try not to use this one unless you have to. Put the cleaned fuel valve back in and try to put in a small inline ceramic filter in the fuel line to keep most of the big rust chuncks out of the carbs. You may still have to remove the carbs and clean the rust out,they are not fun. Put every thing back togethor and put in fresh gas and put in a bottle of Lucas Fuel injector cleaner. The reason in the injector cleaner will break down the rust particles to a smaller size allowing them to pass through the jets in the carbs. I hope this helps.