I disagree a strong odor of gas to be "normal". Not at all.
Petcock on the bike, in On position. (note you must have ample fuel, obviously over the level of the pickup tube)
First...if you pull the vac line on top of left carb....any presence of fuel or any dripping? If so...no good.
Next, pull the fuel line from the carb....needless to say, have a catchcan, rags and such to cleanup...no need to elaborate, it may get messy, so be prepared. Simple common sense applies.
Your fuel line is now removed from the carb, after the initial drip....does dripping continue unabated? If so...no good.
Now providing a vacuum source to the vacuum line...fuel should flow from the fuel line (be prepped...use your catchcan!) . When vac source is removed...the fuel line should no longer flow at all (after the residual fuel has stopped dripping)
Don't become a petcock sucker...get one o' these to provide a vac source...go easy...very little needed to actuate the diaphragm valve
Recommend you read that other thread too. @
DannoXYZ left a link to petcock rebuild...may help you envision what you are doing.
Flow testing can be done, petcock removed, on the bench, too. Using appropriate sized diameter hose (and length to whatever you choose) on fuel and vac lines,
Blowing INTO the fuel line should be absolutely no air flow...UNTIL you provide vac to the vac side, should then allow your bad breath to pass into (and through) the petcock...remove the vac source again to verify no air flow through fuel line.
Bench testing only takes a moment...no need to become scientific or fancy. Its simply go/no go.
The rest up to you...good luck with it, go get 'em.