Well, not sure what I did, but maybe you guys can shed some light.

My bike took a turn for the worse yesterday, about 24 hours after the carb synch. Basically became hard to start.

I just took the carbs out to have a look, in hopes of spotting a problem. I basically took the whole thing apart, inspected, cleaned and put back together, section by section. Float valves, (which area little worn) jets / holders / needles, pilot screws (being careful to put them back in and then backing them out the same number of turns they were in originally).

I just THOUGHT it was running bad before. It doesn't want to idle at all, it 'chugs' at idle, and is VERY slow to respond to throttle input. It almostprefers to die when throttling, but will eventually gain RPM. After gaining RPMS and lifting throttle, it holds high rpms on its own for a very long time before slowly dropping back down.

The only thing I can think to change is the pilot screws. Do they need backed out / turned in to adjust mixture? I have no idea if it's getting too much gas, or too little.

If anyone has an idea, I'm all ears!

Thanks

 

does your intake boots have a hole in them anywhere ? try starting it and revving it up and spraying a little starting fluid around them, if it dies, theres a leak somewhere on the intake side. the only thing that turns my suspession that way is you said it will stay running with the hi rpms. my zxy would not stay lit under 6000 rpms. red lights were a bitch

 

I'm officially a bonehead. After my original post, I went back out and took the carb off again. While doing that, I noticed that I had fogotten to tighten the carb side of the intake boots. I saw it and wondered if that was my problem, but since I had already torn it apart again, I gave the carb another once-over, triple-checked the pilot screws and put it back together again. This time I tightened both ends of the intake boots, and viola....back to normal. It runs almost exactly as it did before any of the problems began.

Funny thing is, after all this, I still have an unsteady idle, although it isn't quite as bad as before. The only think I can think of now is valve adjustment, which I'll tackle another day.

Thanks for the reply.....you were right!

 

Well, you were right about the boots, but as it turns out, it's not fixed. It was running exactly as it is supposed to when I finished it up. Put the side panels back on, buttoned everything up and left it sitting for a while. I just attempted to leave to go on a test ride, and the bad behavior is back. Long hold time on RPMS, chugging down low. I'm at a loss. The intake boots are tight this time, but it's still sick.

Any other ideas?

 

right on man, go ride it ! or try adjusting the idel from the little black adjuster **** on the clutch side of the bike somewhere in there, not to sure on the 250's where the idle adjustment is.

 

There's an update. It's back to being sick. I don't know what changed between when it was up on the stand and now, but it's back to sputtering down low and holding onto revs. I don't know what else to do with it besides take the carbs down to Kawasaki and see if they can figure it out. UGH

 

Wow..what an adventure. Took the carb out for the 3rd time, triple-checked everything again, put it back in and it's very nearly back to normal. I'm getting a slight sputter at idle and a small hesitation when throttled from idle. I've backed the pilot screws out 3 turns, as 2.5 was producing a sputtery idle and a noticable hesitation from throttle at idle. Hopefully if I keep messing with them I'll strike a good balance. Wish me luck!

 

How many turns do you have the a/f screw? What is the measurement on the float?

 

How old is the gas? How old is the bike? Oh wait, let me guess its a 94 Ninja? But I wonder if you got rust in the tank or water. Just a thought

 

I've run the tank completely empty, and I've cracked open the float bowls twice. The gas is fresh, the bike isn't. :-) Fuel level in the bowls is right up to the mating surface (within specs according to the service manual). I do need some new float needles...they have wear on the tips.

I've ALMOST got it the way it needs to be. It's running great...actually accelerating better than it did before, but it's holding onto RPMS a little too much during shifts and deceleration. I think I've got it a little too rich. The pilot screws (external screws in front of both float bowls) started off with 2.5 turns to closed, but it didn't seem to run that well on that setting after re-assembly, so I backed it out 3 full turns. I don't think I'm gonna be able to leave it that way. I'll monkey with it more when I get home today.

It may need to be leaned out to run right, I'm not sure yet. I think it's quite rich where it's at now. It barely idled after a 5-minute warm up this morning, so I idled it up to around 1300, and by the time I got to work it was idling at 2500. Something is definitely not set right. If you have any suggestions, please pass them on!