1981 KZ1000 LTD K Model. Runaway Idle on Startup

Hi all. I'm a newbie here but not to bikes. I'm a second owner of a 1981 KZ 1000 LTD (K model) that I bought back in the 80s. It has 20k orig miles and has been in storage for 17 yrs. I finally decided to get it out and get it running. I'm having two carburetor problems: (1) On startup, it idles normally for a few seconds, then gradually increases RPMs until it's virtually running WOT and I have to shut it down. The second problem might be related, and that is: (2) it's backing up a lot of raw fuel into the airbox. I slowed the fuel backup way down by turning the idle screw all the way to zero, but the bike still starts idling at about 2500 and runs away from there.

The vacuum screws could be way out of adjustment, IDK. I literally just got is started last night so I haven't had a chance to try much to fix it.

Any ideas?

KCMike wrote: Hi all. I'm a newbie here but not to bikes. I'm a second owner of a 1981 KZ 1000 LTD (K model) that I bought back in the 80s. It has 20k orig miles and has been in storage for 17 yrs. I finally decided to get it out and get it running. I'm having two carburetor problems: (1) On startup, it idles normally for a few seconds, then gradually increases RPMs until it's virtually running WOT and I have to shut it down. The second problem might be related, and that is: (2) it's backing up a lot of raw fuel into the airbox. I slowed the fuel backup way down by turning the idle screw all the way to zero, but the bike still starts idling at about 2500 and runs away from there.

The vacuum screws could be way out of adjustment, IDK. I literally just got is started last night so I haven't had a chance to try much to fix it.

Any ideas?

Vacuum leak, pilot jets, idle screws?