wont Idle without choke

The bike starts and runs fine so long as i keep the choke on. But it wont idle at all if i take the choke all the way off. It just dies right away. So i have been rideing around with the choke about half on which keeps it idleing right around 1,200 - 1,500 rpms

i suppose i just need to rais the idle but i cant figure out how.
I've got the carbs balanced and the bike sounds good and runs nice and smooth.

 

my machine 750 , has a knurled largish knob in the center of the carbs underneath the carbs facing to the rear, looky about you should see it , turn in to raise idle.

 

Yeah my carbs do have that knob but I have turned it all the way in and out with little to no real effect on the way the bike idles...

When I turned it with my home made manometer hooked up to carb number 3 and 4 it did affect the vacuum but caused no noticeable difference in the idle speed.

 

ok , carb remove and check out time i thinka , check butterfly synk [levels all the same] , might as well do a clean whilst at it.

but as i just red your post again before i click submit you say all that bin done already , checked compressions on da motor? if they ok , what about air leaks at the boots

 

Yes I have pulled the carbs recently and gave them a light cleaning as they were already fairly clean. Though, I didn’t open them from the top. Just took off the float bowls to unstuck a stuck float in carb number 2. Before putting them back on I gave the boots a solid coat of silicon and tested them to make sure they were air tight. I had to sync the carbs after that which went over very well aside from the idle problem. I have not checked compression. But I didn’t think that would be a problem,… if that really might be my problem I can buy a compression tester for about $40.00 but that’s a lot for me to spend if there is something else I should be checking out first. I also pulled the sparkplugs, I have good spark on all four and no carbon build up or an signs of them burning to hot… they looked exactly the same as they did when I put them in 180 miles ago.

 

I see you no mention looking at the butterflys , synced can also mean the butterflys are opening all at the same time manually as there is a adjustement for that , so at a idle setting if one looked at the butterflys to a light source through the carbs the gap would all be the same.

there are more posts regarding that issue Aschulhoff
...

 

so i should pull the carbs again and make sure the butterflys are opening at the same time... by doing that thin wire test i've read about in other threads on here? anything else you think i should check out while i have the carbs off?

 

While you have the carbs off the bike, check the movement of the butterfly valves as you turn the idle adjustment knob!

You should see all the valves open or close as you turn the adjuster in or out!

 

In my limited but recent experience, a "light cleaning" doens't cut it. I don't remember the exact quote, but Robert once said something to me about 'douching the living dog snot' out of the carbs. That's what you've got to do.

From all outward appearances, my carbs were clean (even with the bowls off), but I went through about a half can of carb cleaner blasting it into the pilot jet circuit, letting it sit, then blowing it out - repeating until the stuff coming out was finally clear. If carb cleaner is coming out of the ports in the throat as anything but clear - it ain't clean.

Just my $.02.

 

Yep , Oblivion is right, those carbs are either not clean or miss set and cannot be balanced either. If you have to open the choke what does that tell you? It needs fuel. The choke circuit on these bikes is really an enrichment circuit. It induces fuel to create a rich mixture instead of restricting air. With the choke circuit on, the idle circuit is bypassed when balancing the carbs. Yes it will balance to some degree but it will still be inaccurate. The idle circuit has not be balanced but the choke circuit has been at least at that level of choke applied.
When you cleaned the carbs did you remove the pilot mixture screws? If so have they been reset with a colortune plug? If no then you may be just lean on the idle setting. You are lean for certain. It is just a matter of how. Dirty carbs restrict fuel as do the pilot mixture screw. I would colortune first then you will know if you need to pull the carbs. It will also tell you if your coils and plugs are firing under pressure. I tuned my #4 carb at the NTCC and discovered that the Kuryakyn Laser Node I had put on my plug wire for "bling bling" was keeping my plug from firing with the colortune. It therefore was delivering a weak spark to my sparkplug. So I removed the laser node and my colortune fired like it should. The laser nodes are now in the cabinet in my laboratory. My cylinder was running rich but not from the carb.