Bike idle

Okay this is something I’m just super baffled by……
So I have struggled with a high idle on my 85XJ 700 and in my playing around I have found that if I uncap cylinder 4’s vacuum cap it will idle around 1700 RPMS (if I push the throttle bar down a little with a screwdriver I get it to idle at 900-1100…makes me think the butterfly isn’t closing all the way maybe? Everything seemed to be fine bench sync wise, wet float set is good) but back to the vacuum if I put my finger over the hole the bike revs to 4K RPM’s and once I lift it drops back down! All the idle screws are 3 turns out! Anyone have any thoughts?
Also checked the valves with another guy from the forum and found a 215 shim on the intake side of the same cylinder 4 so I replaced that so it is only .01mm out of spec instead of .5! And I am working on getting the correct shims!!

 

Did you break the rack ? Butterfly seals replaced ? If so your plate is not centered and your synch is off . Did you do a bench synch ? This should get you close.

 

If you push down on the throttle bar....
Carbs, carbs, carbs. Take them off and do the bench synch again, making sure they all close to the same place (against the adjuster for that carb). But first, check your throttle cable isnt too tight....

 

your chasing your tail until you fix your valve clearance. break rack, replace rubbers, clean again without rubbers.
when reassembling, make sure butterflys align. one of your plate screws is sheard off. - if you didn't mess with it your bench and wet and a/f are fine.
when you get to idle @ 1250 , hit me up -schedule a vacuum sync.

 

did you back off of the idle(throttle stop knob) to try and correct the idle?

also confirm choke cable is connected to the choke and not throttle position.

when you use the choke to start the bike as bike warms idle will climb to 4 k untill you back off of the choke.
idle is 1050 spec 1100 or 1200 is ok .

Idle will be hard to set untill you ride the bike for 10 or 15 miles to fully warm bike then dial the idle to 1100 rpm