Carb help on 82 kz650

1st post....hows it going Kzriders? Seems like everyone has some good advice so here it is...

My buddy has this 82 kz650 with 4 diaphram style carbs. It is completely stock and still has all emissions hardware, airbox etc. It didnt run all that well and someone pulled apart, Before I go for it I just want to make sure i have it all right so heres a few questions.

1. Theres 2 petcock spouts, one is the main fuel line....where does the other hook up?

2. Do the emition hoses that go to front hook up to the 1&4 carbs?

3. jetting is 37.5pilot(with a weird plug over it), 107.5main, 4out airscrew located on top of intake side.......is this the best jetting??? what is the weird plug ??

4. if all else fails he wants to put on emgo air filter pods.....what would best jetting be in this case?

5. can you get rid of all the emissions hoses?

Howdy. The fuel line connects to a Tee between the #2--#3 carbs.
The petcock vacuum line is connected to either a port on the #2 carb or the #2 carb holder (not really sure).
The small tubing for the air injection system is connected to either the #1 & #4 carbs or the carb holder ports (I don't know if your bike has the brass nipples on the carb holders).
The vents are connected to the Tees between the #1 & #2 and #3 & #4 carbs.
The vent tubing on my bike is routed over the airbox shoulders & is fitted snugly between the airbox & side covers.
Any unused vacuum ports should be capped. Replace the caps if they're hard or cracked. The auto parts store sells them. Do not cap the vent ports - install tubing on those ports.
If the airbox ducts are hard or cracked, you may need to replace them. Z1Enterprises.com may have them.

You can eliminate the air injection system. You'll need to cap the various ports. Some folks install block off plates on the valve cover.