kz 750 idling high

I just bought a 750 ltd
when i start her, she idles around 750-1000 rpm, but after running her for a about an hour(long after being warmed up), she will Idle at around 2500-3000 rpm
buddie of mine has a 440ltd, when he heard it he was puzzled, i don't really think this is the Carb, sounds more like a valve sticking.

any1 have any idea what might be causing this.

Thanx
Marc

What year bike and is it a twin or four cylinder?

the bike is an 81 and it is a 4 clyinder

thanx
Marc W

have you tried adjusting the idle control? it's a choke like nob in between the two middle carbs, that sounds like it could be your issue, To lower the rpm you have to turn it to the left counter clockwise.

When you turn on the bike do you choke it?

i don't think its the idle adjuster
i can run the bike for 30 min on a short drive, and it won't accure
but when i'm our for an hour or so, then it idles high
like i said in the first post, it sounds like a valve.
like the heat from the engin causes one of the valves to expand and stick, just wondering if any1 had ever had the issue, or moght know what it is.

The high idle may come from an air leak.

Next time it idles high stop and spray some WD-40 on the intake manifolds. If the idle changes when sprayed, then you have a leak and should buy some new manifolds or try to jury rig a temporary fix. Do the manifolds have any cracking you can see? It may be as simple as a loose clamp too.

I don't think a sticky valve would cause a high idle, in my mind it would make it run slower not faster.

what ended up happening with your problem? b/c my '80 750 LTD does the same thing. I've isolated the problem to the throttle assembly. The throttle cable itself will go lax but the actual throttle connected to the carbs doesn't fall back down all the way(if i push it down with a screwdriver the bike will go to its normal idle).

my money is on the 3 screws that seem to be adjustable (throttle stop screws?) that connect the throttle to the carbs, they have a spring around them and are in some threaded housing.

anyone have any tips for the proper way to adjust these?