83 kz550 now starts but idles way too high.

Okay so I got the bike started but it idles at what seems like full throttle. The idle adjustment is all the way out so the butterflies should be closed, the air fuel mixture screws (pilot screws) are at 1 and 1/4. My intake boots are tightened and my vacuums are all capped off except the one that goes to my petcock. Anyone have an idea why it's idling so high. Anything would be appreciated.

Are you using the stock air box or pod filers?

I'm using the stock air box

The plugs that I believe you're talking about are fuel/air mixture screws. If you have a US model they should be capped off. If they have been drilled out it means a previous owner has probably adjusted it for some reason. A good place to start is by lightly seating the screws and then turning them 2-2.5 turns out. I would also check your fuel level in the carbs using the clear tube test

The caps have been removed on my bike for the fuel/air mixture screws, but I have them set at about 1 and 1/4 turns out, so tomorrow I will turn them out further and give it a shot. The plugs I mentioned are what I believe to be rubber and sit over the pilot jet, number 92055 on the carburetor parts schematic www.cmsnl.com/kawasaki-1983-kz550-h2-gpz.../partslist/6841.html .

Thank you for your responses also.

Anybody have any idea?

Perhaps the throttle cable or carb throttle assembly is binding for whatever reason. Could manually hold the carbs closed to see whether it makes any difference.

If not already done, would also use a strobe type timing light to visually inspect and confirm proper functioning of the timing advancer (which might be stuck in the advanced position and thereby failing to return to its closed idle position when the throttle is closed).

There might also be an air leak -- somewhere, for whatever reason -- that's causing a racing idle.

Check for:
• defective plugs on the vacuum nipples,
• loose carb holder clamps,
• torn carb holder,
• carbs not fully seated into the carb holders,
• a cracked or loose vacuum hose connection at either end,
• leak incident to clean air system,
• cracked worn out carb holders,
• missing or damaged o'rings on pilot adjustment screws,
• etc.

With engine running, can spray WD40 about the carb holders and any other suspected air leak sources to determine whether the WD40 is being ingested to affect the idle speed and/or cause smoke from the exhaust.

WD40 is a little messier than other type sprays such as carb cleaner or propane gas, but WD40 most clearly indicates evidence of an air leak, especially the exhaust smoking.

Good Fortune!

I would start by disconnecting the throttle cable at the carbs. If you do that and the engine still idles high you will know for sure that the problem is in the carbs and not the cable or handlebar throttle. If it idles normal you will know the problem is in the cable or handlebar throttle. Ed

Let me start by saying thank you guys for posting I really appreciate it, and I am sorry for the delay in responding. College/Work plus the wife keep me on my toes. Ok here is the update: I checked the throttle cable and it has some play, and when released it functions correctly with no binding. I let the bike sit for a day and went and started it and had to use the choke to get it fired up and it seemed to idle okay for a short amount of time( maybe 4-5 minutes) and then it started going higher and higher to the point where I killed it because it sounded like it was at full throttle. Also when it started to increase in idle I took some wd-40 and sprayed it around my boots going to the airbox, my intake boots, and my vacuum nipples and it seemed to have no effect. So I Guess my question's would be is that consistent with an air leak still? or is that a symptom of the stuck timing advancer? Or does anybody have some more insight as to what I might check into?
Thanks in advance.

Also make sure you are spraying at the vacuum port on your petcock and the clean air emissions unit underneath your gas tank attached to your valve cover (if you have that). Those are both fairly common places for a vacuum leak. I've found that wd40 isn't the best thing to use for finding the leaks because it doesn't cause the engine to make a huge noticeable difference in idle. I would suggest using carb cleaner.

Hey Gordo! No expert here, but thought I would throw this out there...My 650 (when cold) needs to start on choke...It will rev like crazy if you walk away as it is warming up...I progressively "feather" the choke down for mebbe a minute until she is fairly warm, and idling normally...Re: spraying carb cleaner around airbox boots/carb mounts, etc...this test really needs to be done at as low an rpm as you can establish...at idle, the vacuum is much higher and will draw the vapors in much more readily.

I ran into the same issue. I'm not pretending to know what I'm doing, but the choke was sticking - (gotta love Nebraska dust!) when the choke is fully open, it manually opens the throttle just a little. I was able to free mine up with some Seafoam and patience; just worked the choke back and forth until it leveled out.

Good luck!