86 VFR700 High Idle after warm up

I recently picked up an 86 VFR700. After the engine gets a chance to warm up the idle climbs way up to 4000(ish) rpm and never comes back down. The guy said he had recently replaced the carb O rings and had not had a chance to sync them since. Is this possible. I am currently whipping up a dyi vacuum meter to try and balance them. What other things might I want to inspect first before trying to sync the carbs?? Bit of a bike noob here but any help would be extremely appreciated.
Thanks

 

you already tried backing out the idle speed adjusting screw ?? does the bike idle OK before warming up ? check that the carbs, boots and cylinder intakes are fully seated. spray carb cleaner around the boots while running to check for air leaks. O-rings ?? which ones ?

 

Have not been able to locate the idle adjust screw...when i plugged in my vacuum meter it said that the front right carb (#4?) is pulling the hardest by a substantial amount. I will check for leaks tomorrow. It seemed to idle somewhat smoothly when it was colder but at higher rpms seemed a bit rougher. as far as O rings I do not know I texted him so we will see what he says.

 

Well i decided to say screw it and get to know the girl so I pulled the carb today and did a full clean and bench sync. One of the boots looks less than ideal so guess theres a chance it was leaking.

With the carb off i noticed a bit of carbon build up on the plunger looking guys (valves?!?). Saw some videos of people on the internet pouring some cleaner in there. Is this advisable or might i do more harm than good? Thought it made since as i have the carbs off

 

carbon there is normal, so don't do anything. carbs are fragile; don't drop them !

remember, you can't be certain slow jets are fully clean and open until you can push a .010" wire through the jet.