Smell your engine oil for a gas smell if there is ...change the oil. Stock carb in 81 is Keihin(not CV type) When you park the bike turn off the gas at the fuel shut off at the tank. They will allow fuel past the float valve whether clean seated right or what have you, and could get into the intake, wash down cylinder walls and contaminate the engine oil with fuel, all the fuel might not get out the overflow tube. with an old bike you have to develop old habits....shut down bike,turn off fuel.
when those carbs work right they're fine..but when they don't ditch em....that's why you see so many shovels with S&S carbs on em. I see a lot of the non CV Keihin's in garages as paperweights. When you feel the need for a new carb pick up a Keihin CV..theyre set it and forget it and work very well.