Opened a can of worms

I have a 79 KZ1000 that had sat for a while and needed some work. I removed the carbs and rebuilt with a kit, changed the air filter, and plugs, (which turned black after running) however, when I put them on I can't get it to idle unless on full choke. As well I have massive hesitation until about 4k rpm them it takes off. Between 3-4 rpm the bike almost stalls, and when you shut of the choke the bike bogs and stalls. I have tried many different adjustments with no luck. Where else should I be looking?

XL777 wrote:

I have a 79 KZ1000 that had sat for a while and needed some work. I removed the carbs and rebuilt with a kit, changed the air filter, and plugs, (which turned black after running) however, when I put them on I can't get it to idle unless on full choke. As well I have massive hesitation until about 4k rpm them it takes off. Between 3-4 rpm the bike almost stalls, and when you shut of the choke the bike bogs and stalls. I have tried many different adjustments with no luck. Where else should I be looking?

First, do you have a manual? If you can find a Kawasaki Shop Manual for your model, it will help alot.
If it was running before, and all you did was the carb rebuild, it's quite possible that you put something back together incorrectly, perhaps the floats are not set right, etc.
Take the carbs back off, go over every setting very carefully. I'm sure you'll notice something.
...and make sure they're cleeeeeean...

mine did that when i got it, I found that after soaking the jets in Berrymans and blowing them out at 125 psi, they worked, I am wondering if you put a filter in the fuel line?
I didnt after soing mine and GOO made its way into the carbs again.:blush: Make sure you put a filter inline.
Also clean out the petcock, mine was sitting awhile also and the rubber busing in the bowl was swelled badly blocking off the fuel flow to the carbs.

No, I have not put a fuel line filter but good idea. Yes, I have a shop book. Hey after going over my logs I realized that the original main jets in there were 102.5 and the kit had 102, would that make a difference? What about this float level is that really important? Also on a 78 how should the pilot screw be set? The book is vauge. As well if I put on air pods instead of the stock air filter is it easier to remove the carbs, or harder to set them? I'm at the mercy of my own skills here the local shop is in another town and booked for weeks, and I have no truck to get it there. Looks like the carbs are coming back off. This is the first 4 carb bike I have had and its been a new venture.

You say the bike had been sitting for while. I have found with my '78 kz1000 a yearly lubrication of the spark advancer unit is a good idea. Sticky advance weights can cause a variety of acceleration problems.

I put in a new carburetor kit this week. My original jets were 102.5 as well and the new ones are 102 and they work well.

I thoroughly cleaned and "Q-Tip" cleaned every hole and passageway I could find. I used one of the old needle valves as a fine pick to get at and clean the really small places where a Q-Tip cannot reach.

The float level was critical! Fortunately, you can get away with a Float Level Detector Jig consisting of:
-One 1/4" to 1/4" plastic vacuum hose union,
-One 6" inche length of 1/4" clear plastic fuel line.

In my ancient Clymer manual the Pilot Screw (Idle gas/air mixture) setting was quite specific at 1 1/8” turns out and then install the Limiter cap (which I don't have)... and that's all? This really surprised me since on every carbureted car or bike I have ever owned the next step was to fine tune by turning counter-clockwise and clockwise to the edges of stall and then position the screw halfway between these extremes. They would idle really well down to a few hundred rpm's. Does anyone know if this is specific to Mikuni carburetors or is my manual just incomplete here?

I use and recommend an inline fuel filter.

What I found was after following the manual meticulously my KZ650 runs almost as smoothly as my wife's sewing machine. So now I'm sold on the step-by-step and by-the-book method. It was worth every minute.

I hope this helps. Go get'em and best of success!

The internal passageways inside your assembly associated with the pilot system are not clean... fuel is being obstructed and your pilot system plus possibly the air jets associated with the pilot system and main circuit are very likely clogged and need cleaning. The bike is running very lean until it starts getting on main jet.

Oh yeah... the #102 and #102.5 mains are virtually the same size... aftermarket manufacturers often just leave off the .5 when they stamp the heads of the jets. Will make absolutely no difference in performance.

Post edited by: wiredgeorge, at: 2006/07/17 10:32

Thanks for all the advice, it looks like this is a common issue with these bikes. Do you recommend that I just clean it up and take it to a shop to get mechanically sync? Hey what is the best tool to use for setting the float levels?