KZ250 Single; Starts, revs itself, pops, dies

Hey everyone. Just got myself a 1981 KZ 250 single cyl. and I just cleaned the carb with a lemon juice boil. and re-installed it on the bike. I turn the bike over, she revs up by itself, then slowly drops, and stalls. If I fiddle with the choke, I can keep her running, but if I even try to crack the throttle, she stalls. The exhaust is broken right near the front peg, if back-pressure is an issue at all.

Is it running too rich? The pet cock operates properly and does not leak. Fuel filter right near the carb is clean and free of blockage, and I can see the fuel level inside. I know for a fact I am getting spark. I don't have the points ignition, it's an Ignition module box (just to re-iterate, as I've been asked already)

Any idears? Any questions, please feel free to ask. Thanks!

your idle circuit is clogged and it needs the carb taken off and "all" passages blown through with carb spray and compressed air and it will be fine

look in the book for the carb diagram and make sure you find the idle circuit and clear it

maybe another part is clogged but the fix is the same....

Yeah, I followed the tutorial as to cleaning the carb located here:

cycles.evanfell.com/2008/09/how-to-clean...retor-the-right-way/

But I don't have a compressor, so I really just let it drip dry of WD40 after I cleaned all the lemon juice off it. I'll do the process over and be sure to clean it and find a way of blowing the passages out, then try again. Thanks!!

Carb at hand may not be exactly like this diagram, but may help to use a can of pressurized carb cleaner to spray through the pilot circuit.
The main idea is to assure pilot mixture flow into the carb throat.

Being able to fiddle with the choke to keep it running indicates that some fuel mixture is getting into the carb throat via the separate choke circuit.



And WEAR EYE PROTECTION while spraying, because the spray always backfires, ALWAYS.

Good Fortune!

Ok, re-cleaned and used some ultra-tiny stainless steel wire, as well as air-hosed it dry and free of any debris, and I am still getting the same issue. Starts(on full choke only), revs itself up, pops, and dies. And it's consistant.

Is this a lean condition? Would this be due to a low fuel level in the bowl? I'm totally confused as to what it could be.

did you pull the jets out?

I did. when I pulled the pilot jet (the larger one in the bowel?) the jets were all fine, but the cavity was a little dirty, but I cleaned it out. I'm about ready to pull and dis-assemble again, so that I can take pics and show everyone, in hopes for answers.

FYI, is it supposed to have the rubber plug over the jet itself, correct?? It's a Keihin 34mm carb

slow jet is the little one off to side.

main jet is the big one in middle of carb

one other thing what is your air mixture screw set at?

And the pilot jet is the one under the rubber plug in the bowel, correct? Think my fuel float level is too low?

P21 wrote: one other thing what is your air mixture screw set at?

Errrrr, where is this located? lol

Again, from what I gather, I have a Keihin CVK 32mm


EDIT: I may also look into replacing my in-line fuel filter, to see if that's the possible issue as well, as it sounds like I might be starving my carb