Kawasaki Ninja Forum banner
1 - 9 of 9 Posts

·
Registered
Joined
·
42 Posts
Discussion Starter · #1 ·
Hey guys n gals. I bought a 98 ZX9C today and the guy that I bought it from was going over all the problems he had with it. First, The bike Idles at 4500 - 5 grand!! n that's not good. I do not know where the idle screw is, but I know it could be a number of things. Second problem probably is related to the first. When I drive it, and come to a stop sign or a red light, when I clutch it, I have to feather the throttle a few times and then it will idle (still about 5 grand). If I just clutch it to a rolling stop without feathering the throttle, it will die and NOT crank back unless I choke it. then it will crank and Idle high again. Any suggestions? Also it has a low RPM sputter, but if I hammer on it, it will scream up until about 90 MPH. then starts cutting out. I love this site, because most of you guys should be experts. Yall are awesome so I know it will be right soon, Thanks again!
 

·
Registered
Joined
·
674 Posts
#1 - I wouldn't ride until you have this sorted out.

Find the idle screw. Check the routing and adjustment of the throttle cable.

See if the throttle are snapping shut after you move it to wide open (engine off).

The symptoms sound like a severe vacuum leak. Check the tightness of the clamps around the carbs. With it running, spray some WD-40 (or almost any type of spray) around the intake boots where the carb attaches to the engine. If there's a leak you will hear a change in RPMs. The rubber boots frequently crack with age, so it's possible you need to replace all of them.

The pilot jets (among other things) in the carbs may also be gummed-up, and the carbs may need to be removed and completely cleaned.

Did I mention - don't ride it until you have this figured out!

Try those things are let us know what you found.


Jay
 

·
Registered
Joined
·
42 Posts
Discussion Starter · #3 ·
I pulled carb unit, but cant separate them to clean them and tighten a loose throttle screw. I read that they can be cleaned as a unit. one BIG problem I noticed is that when its running and you look down at the carbs, the little gate on the far left baffle is vibrating open and closed and the others are not.
 

·
Registered
Joined
·
674 Posts
Most of the issues will be in the float bowl, so you don't need to split them.

Pull and carefully clean the jets (especially the pilot). Use one thin wire from "stranded" copper electrical wire to go through the jets. Insert it through the jet and spin the jet around it while spraying with carb cleaner. Be sure to clean all of the tiny cross-drilled holes also.


Jay
 

·
Registered
Joined
·
42 Posts
Discussion Starter · #5 ·
#1 - I wouldn't ride until you have this sorted out.

Find the idle screw. Check the routing and adjustment of the throttle cable.

See if the throttle are snapping shut after you move it to wide open (engine off).

The symptoms sound like a severe vacuum leak. Check the tightness of the clamps around the carbs. With it running, spray some WD-40 (or almost any type of spray) around the intake boots where the carb attaches to the engine. If there's a leak you will hear a change in RPMs. The rubber boots frequently crack with age, so it's possible you need to replace all of them.

The pilot jets (among other things) in the carbs may also be gummed-up, and the carbs may need to be removed and completely cleaned.

Did I mention - don't ride it until you have this figured out!

Try those things are let us know what you found.


Jay




Ok Pulled the bowls on the carba and dod a carb job on em. WHEW!!...lol... I did find the idle screw. someone has twisted it odd, so it was just the wire cable sticking out (which I was still able to adjust) After cleaning everything and putting it back together, It still did the same thing. I sprayed carb cleaner on all vacuum hoses and the boots on the intake. no leaks. I tried idling it down and if you idle it lower than 4 grand it drops and dies. it does run at 4 grand but it surges. I idled it to where it was barely under 4 grand so it drops and dies unless I throttle it. New plugs, fuel filter, and firing on all 4......
 

·
Registered
Joined
·
42 Posts
Discussion Starter · #6 ·
Most of the issues will be in the float bowl, so you don't need to split them.

Pull and carefully clean the jets (especially the pilot). Use one thin wire from "stranded" copper electrical wire to go through the jets. Insert it through the jet and spin the jet around it while spraying with carb cleaner. Be sure to clean all of the tiny cross-drilled holes also.


Jay


done....same problem I posted what all I did in previous post as you were posting this..lol Thanks Jay
 

·
Registered
Joined
·
674 Posts
I would say the low-speed (pilot jet) or the related passages have to be blocked. The fact that it surges as you drop the RPMs makes me think it's leaning-out as you drop the slides, then runs out of fuel. Are there any air-bleed holes in the venturi area of the carb (the back, where the air enters) that may be plugged?

Did you find the idle mixture screws? That's another thing to check and adjust. Note that some of them are "air-bleeds" and others are "fuel-bleeds". That means turning the screw in or out will have the opposite effect depending on which one your carb has. You'll have to check the Internet or a service manual to see which it is.


Jay
 

·
Registered
Joined
·
42 Posts
Discussion Starter · #8 ·
I would say the low-speed (pilot jet) or the related passages have to be blocked. The fact that it surges as you drop the RPMs makes me think it's leaning-out as you drop the slides, then runs out of fuel. Are there any air-bleed holes in the venturi area of the carb (the back, where the air enters) that may be plugged?

Did you find the idle mixture screws? That's another thing to check and adjust. Note that some of them are "air-bleeds" and others are "fuel-bleeds". That means turning the screw in or out will have the opposite effect depending on which one your carb has. You'll have to check the Internet or a service manual to see which it is.

Jay
I will check again for vacuum leaks. As far as the carb adjustment what are they supposed to be set at stock? I cant get my hands on a manual anywhere. The two closest dealers to make our 45 minutes away and they both are out
 

·
Registered
Joined
·
674 Posts
I will check again for vacuum leaks. As far as the carb adjustment what are they supposed to be set at stock? I cant get my hands on a manual anywhere. The two closest dealers to make our 45 minutes away and they both are out
If you didn't get any change when you sprayed the intake boots you should be fine as far as vacuum leaks go. I think there are carb issues/blockages of some kind.

There should be a free service manual available on-line somewhere, or possibly a download for a fee.

Explain the part about the vibrating baffle again - I'd look into that closer.

We'll keep trying to sort it out, but there may be a ZX9 forum with more specific info and answers - I'm just about out of ideas....


Jay
 
1 - 9 of 9 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top