replacing kz 900carb holders

HELLO IAM NEW TO FORM 
i AM REPLACING THE CARB HOLDERS ON 76 KZ900 BIKE STARTS UP AND RUNS GREAT BUT AFTER ABOUT 1/2 HOUR THE IDLE STARTS GOING UP TO 3000 AND UPWARDS    I HAVE NEW ONES FROM Z1 ENTERPRISES MY QUESTION IS ARE THE GASKETS THAT HAVE TO BE REPLACED OR A SEALENT THAT IS RECOMMENDED                                     i BELIEVE IF I REMOVE THE GAS TANK AND PODS THERE IS ENOUGH ROOM WITH OUT TAKING THE CARBS ALL THE WAY OFF JUST LOOKING TO DUE IT THE EASIEST WAY WITHOUT REMOVING THE CARB CABLES                                                                                                                                                                                                                                                                                                                   DTHANKING YOU IN ADVANCE TOM C

No gaskets. The new carb holders will have a lip molded into them. It seals them against the head. It’s not hard to remove the cables from the carb rack so you can pull them all the way off the bike. It’s a good opportunity to inspect the throttle cables and get some lube in them. There is a process shown in the factory manual. It works just as good to hold the carb end of the cable up. Hold it by the barrel fused to the cable. Use some light oil like 3in1. Touch the tip of the oil spout to the cable just below the barrel and slowly drip oil. You will see the oil follow the cable down and into the outer casing. 

Before removing the old carb holders you will need a good JIS screwdriver. The holder screws look like Phillips but they are not. Unless of course someone has swapped in some replacement Allen head cap screws. 

The easiest isn’t always the best practice. 

I usually put a very thin layer of 3 Bond on the metal face before attaching the gaskets.

If your problem with idle continues you may want to look at your choke plungers for a solution.  There is a rubber seal on the bottom.  After a few years they will begin to leak a bit.  They can be replaced.  There is a member here who does them.