TOPIC:

So my 1982 kz440 is finally running and will idle at 1000 rpm with the choke on. I am still waiting for the air cleaner element so for the time being I put an air filter from another bike on the intake of the air box. As I said I got it to a steady idle and it will stay that way as long as it is choked. If I give it any throttle the engine revs up to between 3 and 4000 rpm and won't come back down. Also when I open the choke it will rev up between 4 and 5000 rpm and never come down.....any thoughts would help. Im scratching my head on this one.

Carb holders leaking.

On the air box side or on the engine side? I've done the starting fluid leak test and I had no vacuum leaks as far as I could tell.

Clearly a mixture problem.  In order to achieve a nice steady idle you need...

1) clean carbs with fresh O-rings throughout
2) vacuum sync the carbs
3) NO AIR LEAKS.  Spraying crap in the carbs will only identify gross air leaks.  
4) entire air path sealed, including a proper air filter, airbox sealed, airbox boots not leaking where they attach to the carbs.
5) carb boots on the cylinder head must be soft, pliable, and free of cracks or leaks of any kind.  Replace these boots if they are original.  It's like putting money in the bank.

I did a complete carb rebuild all new jets, diaphragms, and o-rings. Now my carb boots on the other hand are rock hard, no visible cracks but I should probably go ahead and replace them eh? Now one thing I cant seem to find on the carb is the fuel/air mixture screw....is there not one on these kliehn cv carbs? 

The pilot mixture screws are on top of the carbs on the engine side, underneath aluminum plugs. See pp. 54-55 in the service manual. If the plugs are still in place, then you did not completely clean the pilot circuit. To remove them, you will need to VERY carefully drill through the cap, but do not hit the screw with the drill bit. You can wrap some tape around the bit very near the end, so that it just penetrates the plug. It is thin aluminum. After making a hole through the plug, use a curved dental pick or similar tool to pry the plug out. Now very carefully screw the adjustment screw IN until it just begins to seat, counting how many turns it takes, including fractions. Each carb may be different. That will be the starting point for adjusting when you put it back together. Then take the screws out. There will also be a small washer, an oring  that needs to be replaced and a spring. Pay close attention to the order that they come out. They must be replaced in the same order. Now you can clean the tips of the screws and the rest of the pilot circuit. You can try using the straw on a can of carb cleaner and noting if the cleaner is spraying through each of the tiny holes in the throat of the carbs. If they are all clear, then follow with compressed air.
If one or more of the holes seem to be plugged, and just to be sure they are really clear, you can use a steel E string for a guitar to clear any remaining debris. The smallest gauge the store carries will do the trick.

Yes, the carbs really need to be off the bike to do this.


www.kzrider.com/modules/ServiceManuals/kz440.pdf


P.S. If the carb holders are hard, there is a 99.876% chance they are leaking.

wrote:

I did a complete carb rebuild all new jets, diaphragms, and o-rings. Now my carb boots on the other hand are rock hard, no visible cracks but I should probably go ahead and replace them eh? Now one thing I cant seem to find on the carb is the fuel/air mixture screw....is there not one on these kliehn cv carbs? 

If you didn't remove the pilot screws then you didn't do a "complete" carb rebuild.  The pilot circuit has some of the smaller passages on the carbs and they plug up very easily.  There is a lot more to a "carb rebuild" than installing some aftermarket carb kit parts (which may not match the originals.)

New jets? Are they genuine Keihin? Did you also replace the needles?

Maybe it´s sounds a little bit stupid but, did you know the idle adjustment screw?
Also check your throttle cable slack and throttle cable routing.

Here's the update. I ordered new carb boots on the engine side. Took the carbs back off the bike and got the mixture screws visible. Took them out and low and behold both were gunked up like no other! I went ahead and put the original jets back in the carbs after tediously running a guitar sting through each and every hole. I got new orings and springs put on the mixture screws. Just gotta wait for those new boots to arrive and reassemble the ol girl.....I feel like I'm getting close to finally getting to ride. You all have been a lot of help! Thank you all so much. Ill update tomorrow on my progress.