On the bottom of your carbs is the air/gas mixture screw. This is a slotted screw in a shroud or sleeve. The adjusting screw device fits over the shroud centering the blade portion of the device.

+1 on what gmacarthur said.

Additionally, what you will want to do is first remove the screw completely and inspect the condition of the sealing o-ring on the stem. This is a common #60 o-ring you can buy at the local hardware store in a 10 pack for $4. If the o-ring isn't perfect looking then install a new one.

Upon re-installation, turn the screw inward (clockwise as you lay on the ground and look up at the screw head) until you feel the resistance of the screw bottoming out. Then back off the screw (counter-clockwise) typically 1-1/2 turns. This is usually a good starting position for carb tuning. Once the engine is fully warm, you can turn that screw back and forth to achieve fastest running speed on that carb. That will usually happen somewhere between 1-1/4 to 1-5/8 turns out.

Although you'd think the setting would be the exact same for both carbs it may not. This could be due to many things such as idle setting, cylinder compression, plug condition, o-ring condition, etc. If you can't hear the difference turning the screw makes, then don't worry about it. Most of the motorcycling world is riding around on the initial setting of 1-1/2 turns !! 😛