yep you could have a small pin hole in your line

where are the bubbles coming from, the tank end of the line or the carb end?

if bubbles appear at the tank end first then the air leak is from that end of the line. the cap may not fit tight (adjust, or new seal), the fitting itself may not be tight (check and tighten if needed), the line may not fit to the nipple tight (use zippie tie or buy fuel line clamps to cinch tube)

if bubbles come from the carb end first then your leak is here. tube may not be tight on nipple (zippie tie or fuel line clamp), carb may not be seated properly (loosen side bolt for carb, push down on carb w/thumb retighten)

if you have a filter then the leak could be from here too. check for the fitting issue (use zippie tie or clamp), make sure the filter is closed properly and tight.

these are cheap checks that you should do first. they've all been issues for me before at one time or another. cost nothing but may fix the problem

fuel from the exhaust is a tuning problem. tune her up a little.. good luck