1980 Honda CX 500 A "stablise" Questions

...petrol the engine is quite happy on ether fuel the motor may be unsettled for a while but will stablise if you change over from one to the

i have 99 sportster883- been sitting for a while-it startes up right away with choke when i adjust choke to normal riding position or if i trottle it dies- seems to be air intake issue ,maybe ,how do ...