ZX900 Starting/Idle problem

[wernerk]

I have a 1985 Kawasaki ZX900 Ninja that I got from a friend and have been restoring. It sat for 10 years without running. The engine stopped running on him and he never fixed it. He ordered a spare engine for it since he thought that was the problem. I installed the spare engine, but I am using the original carburetor, he thinks the carburetor has a jet kit installed, but I don't know if there is an easy way to tell. The exhaust system is a Vance-Hines dual exhaust (4 into 2). I did clean the carburetors once, but haven't rebuilt it. I have the original gas tank off the bike since I will be repainting it since I sealed it internally since it was starting to rust. I am using a small plastic tank from my lawnmower for my fuel tank. When I tried to start the engine, it would turn over, but wouldn't even try to fire even with the choke lever pulled all the way back, The linkage/cable is working. I sprayed some starter fluid into the carburetors and then tried again, it started and the RPM's soared over 3000 then dropped back down and died. I sprayed starter fluid in again and started it again, but this time I gave it some throttle when it started and I can keep it running with the throttle as long as I don't let it drop below 1000 RPM, it revs up to and over 4000 easily with no hesitation or missing. This of course leads me to believe that the engine is okay and that the problem is with the carburetor. Can someone guide me in what I should do next and give me some tips on what to look for? Do I need to clean the carbs again and/or rebuild them? I have replaced the vacuum lines and I currently have them all plugged, since I don't have the Petcock hooked up at this time since I am using a lawnmower tank that is being gravity fed to the carburetors. I thought about converting this bike to fuel injection, but I do not know anybody that makes a fuel injection kit for this bike. Any help will be greatly appreciated, if you know how to identify if this has a jet kit and what stage it has installed that would be good to know also. I have made no adjustments to the carburetors since I figure they should have been right since the bike used to run up until it quit, at which time my buddy never thought that the problem could be carburetor related.

[StarGate]

Have you tried to adjust the idle a bit higher to see if it will hold a steady idle around 1200 rpm? To see if it has a jet kit installed you will need to pull the carbs off and remove the float bowl. Use a magnifying glass if you need to but look at the main jet and see what # it has stamped on it. Then compare that to the stock size jet. You may have to remove one of the jets to find the #.

[Ericthejet]

132.5 is the main from the factory. Anything else and someone has been in there. Pilot is a #35
Yes, so I have one of these bikes. Clean those carbs very well and be sure to test the float shut off valve by turning the carbs upside down and blowing into the fuel line. You should not be able to move any air, flip it over and try again, air should move thru now.

Read up online on cleaning carbs and the bits to pay attention to. You may need to soak some parts overnight. Clean everything that the carbs touch before you remove them to minimize dirt, use wd40 to lube up the intake side of the carb and the airbox side as well to make it easy to put them back into place.

[BR549]

Originally Posted by wernerk

I have a 1985 Kawasaki ZX900 Ninja that I got from a friend and have been restoring. It sat for 10 years without running. The engine stopped running on him and he never fixed it. He ordered a spare engine for it since he thought that was the problem. I installed the spare engine, but I am using the original carburetor, he thinks the carburetor has a jet kit installed, but I don't know if there is an easy way to tell. The exhaust system is a Vance-Hines dual exhaust (4 into 2). I did clean the carburetors once, but haven't rebuilt it. I have the original gas tank off the bike since I will be repainting it since I sealed it internally since it was starting to rust. I am using a small plastic tank from my lawnmower for my fuel tank. When I tried to start the engine, it would turn over, but wouldn't even try to fire even with the choke lever pulled all the way back, The linkage/cable is working. I sprayed some starter fluid into the carburetors and then tried again, it started and the RPM's soared over 3000 then dropped back down and died. I sprayed starter fluid in again and started it again, but this time I gave it some throttle when it started and I can keep it running with the throttle as long as I don't let it drop below 1000 RPM, it revs up to and over 4000 easily with no hesitation or missing. This of course leads me to believe that the engine is okay and that the problem is with the carburetor. Can someone guide me in what I should do next and give me some tips on what to look for? Do I need to clean the carbs again and/or rebuild them? I have replaced the vacuum lines and I currently have them all plugged, since I don't have the Petcock hooked up at this time since I am using a lawnmower tank that is being gravity fed to the carburetors. I thought about converting this bike to fuel injection, but I do not know anybody that makes a fuel injection kit for this bike. Any help will be greatly appreciated, if you know how to identify if this has a jet kit and what stage it has installed that would be good to know also. I have made no adjustments to the carburetors since I figure they should have been right since the bike used to run up until it quit, at which time my buddy never thought that the problem could be carburetor related.

The main jet size for non-California, U.S. bikes is 135. For California bikes, it's 138. Pilot jet size for both is 35. Those numbers will be stamped on the jets. They can be hard to read, though.

Your bike won't start because the starter circuits in your carburetors are clogged.