Climbing Idle on 82 XJ750

Afternoon all.

Get an infuriating carb problem with my 82 XJ750

Bought the bike as a non runner, quickly identified its a carb problem.
Stripped and cleaned the carbs
Got is running but revving its nuts off
Turns out bad routing of the throttle cable was causing it to go tight and be open.

Have since then:
Cleaned carbs again
set float heights
checked valve clearances (re-shimmed three of them)
Checked compression, all between 150 and 155 psi
Bench sync carbs
Properly synced carbs using guages and YICS blanking tool

So now starts on the button without fail, choke if it cold, no choke if its warm.

BUT....

If the tickover (warm) is set to 1000rpm with the tickover screw it will run for a minute or so then stumble and eventually die
If I increase the tickover to around 1100rpm it will run for around 20-30s then revs will climb to around 3000rpm and stay there until I kill it.

If when its sitting at 3000rpm I turn the idle adjuster down ever so slightly it will decrease to around 1000rpm slowly then stumble and die.

It will do the same if the YICS blanking tool is in or not.
Does the same if running on the fuel tank or an external gravity supply.
Throttle cable disconnected to eliminate that as a possible issue.

I've checked for air leaks, both visually and by spraying WD40 around the carbs and inlets, no change.

Havent been out to ride it yet so this is all in neutral without load.

Tearing my hair out with this

 

Additional info, new plugs, new air filter, intake and exhaust system are standard.

 

My 83 XJ650 needs to run on choke for a few minutes, even in the summer. I'll nudge it over to say 2000 rpm and take off riding, then within a few miles just slide it all the way off.

You MUST set your idle screw with the bike fully warmed up.
If you did not perfectly clean your carbs, set the idle mixture properly (I used a color tune) and sync the carbs, you will not get good consistent idle and warm up.

Mark your idle position w/ a sharpie on the side of the carb, that can tell you if the throttle is returning to the same position as you set it.

 

Thanks for the feedback, however all this was when the engine is fully warm.
Throttle cable is disconnected at the carb so its not that, this happens with no throttle input at all, it just climbs after 20-30s of tickover.
Carbs are fully synced using vacuum gauges and the YICS blanking tool.

Although I haven't checked/set the idle mixture, need to dig into the Haynes to make sure that they are correct. Thanks for pointing that out.

 

No manual can tell you if they are correct. There is no correct other than if you set them correct. Same with vacuum balancing.

 

I've experienced the same thing. With the idle set higher, you can take it off choke pretty quick, but tend to have high idle after it warms up. When properly set, you should need choke on until getting some heat in the motor.

 

I will say this all 3 carb/bikes I've set up, the mixture screws were different and not necessarily where a manual said they "SHOULD BE". You have to tune them.
You can manually do it by moving it richer and richer till it starts to go down, then move it back leaner 1/8-1/4 turn. there are different ideas on how to set them w/o a color tune or an O2 sensor

Like I said, if its climbinb 20-30 seconds after starting, then adjust the idle screw so its at the desired idle after say 1 minute. Use choke until its warm