No idle screw adjustment left.

I have an 83 750 maxim . I took the carbs completely apart cleaned all of the inner parts as well. I put the rack back together. I did a fuel height test and ajusted to spot on 3mm. I bench synced to where the butterflys were covering about half of the hole on the top of (ventury tube?) Put the rack back on, it started up. I let it warm up and then ajusted the idle. I went to sync the carbs as i was syncing the rpms would slowly go up, it did this a few times. I got them to sync but the idle stays at about 1500 rpm"s and the ajustment screw is all the way out not even touching the sync arm. I have sprayed break cleaner all over the carbs and intake idle stays the same. anyone have any ideas ?

 

Possible that your choke cable adjustment is a little tight and not fully closing? Should have a slight bit of visible play as the fork finger things start to lift before you see them raising the enrichment shut offs.

 

its still possible that one or more of your butterflies, are holding the throttle shaft open, back off the butterflies at the 3 synch screws slightly untill the revs drop off ,and bike stalls, then put a little pressure on the idle screw till it idles ( some) , then begin your running synch, as revs begin to rise (by becoming in synch) back off the idle screw, i'm sure this is your problem.
what are you using to do a running synch , dial guages ,or a home made tool?

 

Choke cable is like you discribed roaster, nice and loose.I will give that reverse sync a try. Ive got a motion pro and a morgan guage.

 

I’ve had this happen before. When you vacuum synch the bike, you are essentially unbalancing the butterfly valves to even out the vacuum in each cylinder. Bensalf’s suggestion will probably take care of it, but on the off chance it doesn’t, here’s an anecdote…

With my bike, the problem was that one of my fuel enrichment plungers wasn’t bottoming out when the choke was closed. So, that cylinder had a radically different fuel-air mixture and was messing with the synch. If the reverse synch idea doesn’t solve your problem, it’s probably worth checking if there’s something else letting air or fuel into your cylinders unevenly.