Carbs Stick/ Throttle returns

Got my kz1100 started this morning. Seems to run well. When I throttle it up it sticks but the cable is returning to position. It seems like an internal carburetor issue. Any feedback would be great.

it may that a vacuum leak at the carb insolators

Not to appear less than knowledgeable but what are the insolators? I replaced the mounting boots (for want of a better word) It revs up and drops rpm very slowly and at times it climbs a little. Just hate to tear it down, cause I just put it together. But I'll do whatever it takes.

I believe he is referring to the Carb holders/ intake manifolds. Check them for vacuum leaks as well as the small vacuum hoses at the same area. If you still have it, there is a Tee from 1-4 to an Air Switching valve under the tank. That and a line from the #2 carb to the fuel petcock vacuum switch. Then of course there is the Ignition Advancer, which can become sticky and slow to return. That holds the Timing advanced and will cause it to be slow to return to Idle/.

Took a ride. Not a great idea. What' the best way to check for vacuum leaks? If that checks out what is the process to free up a sticky Ignition Advancer? It seems like I saw the T running from 1-4 carbs. I hooked up the hose that ran to the number 2 carb. I was't paying a lot of attention as to where they came because I had taped & marked location when I disassembled the engine.