1982 KZ 550 Won't run off choke

Ok, So a little background first. I just turned 18 and decided to go pick up a road bike to restore now that I finished building my dirt bike from the ground up. (Still have to take my motorcycle license exam)
I wound up buying a 1982 KZ 550 With 9k original miles and a brand new candy apple red paint job W/Metallic flake for 700 bucks.(New tires as well!) Previous owner said it ran "great" when parked a year ago... I anticipated the carbs would be gummed up because he let it set for a year with today's lovely ethanol enriched gasoline. So I get the bike home and put the battery on charge, took the tank off and removed the carbs. Dumped out the toxic waste that was once gasoline in the tank and cleaned it thoroughly. (Now my basement smells great!) I took the carbs apart (not from their housings but I took the float bowls off) and cleaned them. I only had carb cleaner at the time and was in a rush to get the back together so I cleaned them with a rag and carb cleaner and put them back together, Re installed on the bike and BAM! it fires right up with the choke on. Idles around 1100-1400 rpm's. I let it run for 2 min. or so with the choke on, and the second you take it off choke it dies out.
So, this morning I took the carbs back off, took the float bowls off, jets and float out and let everything soak all day long.Then I bought a blow end for my air compressor (which blew up on me this evening... What a day) and THOROUGHLY cleaned them this time. I took a sewing needle that was smaller than holes in the jets and made sure they were not blocked. Blew all jets out with carb cleaner and compressed air. I blew compressed air through all the passages on the carb body, and all the fuel lines. Put everything back together this evening (Lubed external choke and throttle rods/cables with WD-40) and double checked all hoses and lines were routed correctly. Turned pet. to PRIME, put it on full choke (and yes ALL the choke flaps are working properly) and it fires up again. Turned Pet. to ON, let it idle for 3 min or so this time and the same exact thing is happening... You move the choke lever literally 1/8 inch off choke and it dies. Any extra air introduced after the choke plates kills the engine.
Sprayed brake cleaner around all the carb boots (like everyone says to do on the forums... Ive been reading for hours and cant find anyone with my exact problem) and no leaks to be found. The carb boots are not cracked and look new. The fuel line from the Pet. to the fuel rail is new, but all the vacuum hose is factory (but all that looks fine, no cracks/splits)
What gets me is it runs and revs perfect on choke... its like any other carb'd bike/car ive ever owned, except it dies as soon as you take it off choke.
I read the clymers manual and followed their procedure for assembly/disassembly of the carbs. The spark plugs look new (externally) and I pulled them and they look normal.

In all the reading ive been into about these bikes this evening I read that it could be a compression issue or an ignition issue. I think I have ruled out both those... The bike only has 9k original miles.... I mean I could put a gauge on it but is that really necessary? And it runs and revs fine while on choke... so i feel like that rules out Ignition.

Any help would be appreciated. Sorry for typing so much but I feel that all I typed was necessary info... Don't want to be vague like some people can be on fourm's.

My first guess would be the jets are still gummed up but if you're sure they're clean it could be another issue. Are you using the stock air box or the pod filters?

Would suspect the carb pilot circuits aren't yet perfectly clean.

This procedure may help:



Besides perfectly clean passages in the pilot circuit, and an "as new" pilot jet, it's easy to overlook a clogged orifice where the air/fuel mixture exits the pilot circuit into the carb bore (see #6 on the illustration).

Good Fortune!

It is running a stock air box, stock air filter, stock exhaust... heck the entire bike is 98% stock. Right down to the factory lock under the seat and the original stickers with tire pressure specs and valve specs.

Thanks for that Diagram! I guess the carbs are coming back off tomorrow! Ill follow that procedure to a tee and report back tomorrow night with results. I really hope that fixes the problem... I have worked on 10+ LITER Mack, Volvo and Cummins engines that are less frustrating to work on than this thing! Like who on earth designed that air box system where the carbs are wedged between the engine and the air box... Anyways Thanks for the Help!

In warm weather it's not too horrible to get the carbs on and off.

Loosen the clamps much more than it seems they need to be. This is because of the way the carb holders are designed. They have an internal, partial-oring shape molded in and the o-ring goes into the groove on the carb outlet. As you pull the carbs off, the rubber tries to expand a lot, so the clamps must be extra loose.

Also, make sure all of the airbox bolts are loose or out so the airbox can move back as far as possible, easily.

Then sit on the bike, with the center stand, and put your feet on the engine covers that stick out on each side. Then pull the carbs back into the airbox until you can get the nose of the carbs out and tip them up or down. Once they are tipped, they can come out of the airbox boots.

Assembly is similar to removal. Make sure the carbs go all the way on, into the carb holders. Do an eyeball measurement before putting the carbs on so you get a sense of how far they should go on. Or do an actual measurement.

I use a tiny bit of antiseize on the on the carb outlets, but just a tiny tiny bit. This allows the rubber to release easier next time.

As to the dieing problem... Are you sure all 4 are firing? Do a water test on the exhaust pipes to make sure the water dances off each pipe the same way.

These bikes are cold blooded, and on e a cool day, you will need choke for more than 3 minutes while idling.

It's also possible the idle adjustment is just too low. If you rev it, then take the choke off, can you create a smooth idle by holding the throttle steady? If so, then you may want to turn up the idle speed.

When you are ready to fine-tune the choke's fast-idle position, you should check out this link:
home.comcast.net/~loudgpz/GPZweb/TK22mai...astIdleScrewMod.html

The order to check things is :
Compression Check
Valve lash check if compression is off
Ignition timing and advance curve

Then onto carbs:
Fuel level is the first step
Check for clear light through the pilot jets and main jets. The hole should clearly show a perfect circle of light coming through. If not, then there is dirt in them.
The mixture adjustment should only have air going through, so they usually don't get gummed, unless someone shoots cleaner through there.

See my signature for a TK22 carb website which has the port routing for the carbs.

Also, before anything else, get all of the manuals in my signature, and read the valve train warning before opening the valve cover.

Good luck.

Thanks for all the helpful info guys! Patton that diagram of the pilot circuit and how to clean it was exactly what I needed. I pulled the carbs back off this morning, and followed that procedure exactly. Turns out there was some gunk in the #6 hole (#6 on the diagram) of every single carb. Gave everything another check and put it all back together. Choked it, let it warm up for a min or so and decided to try and ride it this time. I made several passes back and forth out my short road (0.3 of a mile long) and then slowly took the choke off and it stays running now! (I am way to excited for my own good) I had to adjust the air screws so it would stay running at idle, but it runs great above 2k rpm's.

Then I developed another problem.

As i was taking the choke off I noticed the #1 carb (The first one if you are sitting on the bike on the left) was leaking (actually pouring a constant stream out the float bow. Yes the drain screw is tight but it still seems to keep overfilling the float bowl and running out. What is my problem here?

loudhvx- I used your procedure for the removal and assembly of the carbs. Loosening the clamps way more than you think is necessary definitely helps quite a bit. And I checked out the carb website... Lots of helpful info there! Once I get this leaky float bowl issue checked out I am going to do the water test to ensure its thumping on all cylinders. What little I did ride it today it moved on pretty quick!

Thanks again ya'll, Once I get this leaky float bowl sorted out I think it will be ready to ride!

Mackman82 wrote: Then I developed another problem.

As i was taking the choke off I noticed the #1 carb (The first one if you are sitting on the bike on the left) was leaking (actually pouring a constant stream out the float bow. Yes the drain screw is tight but it still seems to keep overfilling the float bowl and running out. What is my problem here?

Sounds like a sticky/misadjusted float. Easy fix, since it's on #1. No carb removal. Do you have, or have you made a bowl fuel level tool? (BTW, I'll leave it here, I'm sure others will have better info for you with this.)

Update:
Fired the bike up and let it run on choke for 3 min or so, took choke off and it idles (somewhat poorly) and revs fine, but when you acutally try to ride it it bogs badly and doesn't seem to have alot of power.
Float bowls stopped leaking also.

Hopefully, parts for each carb were kept together and not mixed up among the carbs when reassembled, and it's especially important to keep the float needles and seats together.

A speck of crud may cause leakage through the float valve by preventing complete seating when it's supposedly closed.

Sometimes a leaking float valve may be remedied while the engine is idling and the carb is overflowing by rapping smartly against the side of the float bowl with a plastic mallet or large screwdriver handle which may jar the blockage loose to help float it away. When Lady Luck smiles, the leakage just stops -- and stays stopped.

I don't know exactly why this works, but have often been successful in stopping an unexpected overflow on a freshly reassembled cleaned carb.

And it's fast and cheap with zero disassembly, and won't hurt to try.

In stubborn cases, may chuck a q-tip in a drill and spin it with carb cleaner inside the needle seat. And also inspect the needle tip for excessive wear.

The clear tube test is a good way to determine the true fuel level inside the float bowl of a fully assembled carb, which may be performed with carbs attached to the engine as normal, and the bike on its center-stand or held upright and level.



A tube of correct size may be simply self-threaded into the drain hole.
It shouldn't leak at all. However, minimal leakage won't invalidate the test.

The clear tube test will also indicate any need to readjust the float tangs in order to achieve the correct fuel level.

Good Fortune!

Well, now it almost sounds like the particle that may have stopped the float from closing is now clogging a jet.

Pull your plugs and let us know what they look like. A PIC of the set would also be nice. This should also tell you what carb(s) may need your attention.

Got an inline filter installed yet? Only a couple bucks at any MC shop.

Mackman82 wrote: Update:
Fired the bike up and let it run on choke for 3 min or so, took choke off and it idles (somewhat poorly) and revs fine, but when you acutally try to ride it it bogs badly and doesn't seem to have alot of power.
Float bowls stopped leaking also.

Float valves were probably flushed clean via normal fuel flow.

At what throttle position is the bog? At pull-away from idle? Upon acceleration from any speed?
Could be something other than a carb issue.

Would check functioning of the timing advancer by watching it move quickly back and forth under a timing light while blipping the throttle. The advancer may need some clean-up and lube.

If not already done, would check valve clearances and assure being within specs.

A few seconds after starting a stone cold engine, spray water mist over the exhaust headers to assure combustion in all cylinders by seeing the water sizzle and instantly evaporate off every header pipe.

If water runs down the pipe, that pipe's cylinder isn't combusting (for whatever reason).

Good Fortune!

Sorry for the late reply guys... Just had to have all 4 of my wisdom teeth yanked out yesterday. It will be saturday most likley before im back working on the bike. I will pull the plug set out and snap some pics for you guys.

If the bike is in neutral fully off choke, it has a hard time idling... After you get the rpm's above 2k it revs fine (havent reved past 7k in fear of a still lean condition.) If you actually try and ride the bike you have to give it half choke to take off, Then after you get past about 15mph you can remove the choke but it bogs basically the entire way through the rev range. Around 4k rpm's it picks up a little but will not rev past 5k while riding it. It just bogs out bad.

I still need to do the clear tube test... Does anyone know a ballpark on the OD of the tube? I can pick some up at the local hardware store next time im in town.

Water tested it the other day.... The water steams off each pipe basically the same.

I guess its time to check the timing... If that turns out to function normally then ill check the valve specs.
I just dont get it... The guy who sold it to me was super honest about everything on the bike... He still says that the bike ran GOOD before he let it sit.... Im still leaning towards carb's or timing.

Thanks for the advice ya'll