As Schneider says, the two hoses bring an atmospheric pressure into the carbs, avoiding a vacum to build up as the engine runs. The atmospheric pressure also helps pressing the air/fuel mixture into the jets and into the venturi where you have a low pressure sucking the mixture up.
I would recommend you to do the standard procedure tuning up your bike. That is a valve adjustment job, points gap and timing, cam chain tensioner (if the engine runs) and synchronising the carbs. However, if the bike has not been in regular use for a long time, you have to take them off the bike and clean them properly. To have the complete joy of any vintage MC, this is the only way to go. You can do it yourself, it is not difficult. Use this forum for advice as you go and maybe ask some questions before you take the carbs off. You will need an instrument to synch your carbs, maybe someone on this list around you to give you a hand on that.
These are great bikes - good luck with it!
Some advise to find here:
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