'83 KZ650 / #3 will not fire?

thanks ...so, just swapped the coils to the opposite sides, and fired her back up again: the cylinder not firing did not move, #3 still not firing ....and, once again, if I shoot some starter fluid into the air intake for #3 while running, #3 fires, as I can hear all 4 loud & clear out of the Supertrapp tail pipe for those few seconds the starter fluid is making it to the #3 plug .....so, this is all leading me back to the #3 carb not delivering fuel to the #3 plug ....if there was a valve issue for the #3 cylinder, it would still not fire when shooting starter fluid into the plug - correct ? .....time to pull the rack of CRs and check the jets & whatnot for the #3 carb .....to note: I also just checked each plug for proper spark individually again, all checked good again: sparking away nicely all 4 of them ...also to note: all 4 intake rubber boots that the rack of carbs fit into are brand new too

I have glanced over your thread Freddy, and I believe you are narrowing it down. Perhaps the #3 needle and seat is not letting #3 fill with fuel? If the bowls have a drain screw, make sure it's full of fuel. The passages would need to be plugged up pretty good to prevent a cylinder from hitting. Different throttle positions would more than likely uncover an open one and let it fire.

A motor will also run on WD-40, with the lubricants inherent in it, will not wash down your cylinder walls. (most starting fluids have cylinder lube in them too) 3

#3 carb, as all others, are fully filling bowls direct gravity from the petcock ....and ALL internals on the entire rack of smoothbores have been replaced, and the entire rack electro sound dunk tank cleaned ....I even made sure fuel was flowing to and thru the needle valves with the bowls off & the floats dangling before I did my first mount up of the carbs after rebuild ....so all of this would make it hard to believe something may be obstructing fuel flow / jet spray for #3 only, but crazier things have occurred ....I am running brand new NGK iridium plugs of the hotter / standard range: B7ES ....I may try a colder plug range, like the iridium NGK in the B8ES range ....gap is perfect .032 on the plugs, and as I mentioned, all 4 are sparking nicely ....mentally puzzling for sure why #3 continues to not fire, but I'm getting closer to nailing down why ....

Obviously, something was missed, or this would not be an issue. Pull the carbs and use brakkleen or whatever you use with >EYE PROTECTION< and shoot through all of the passages. If I have to, I also poke a stripped bread tie through the passages. A plugged passage will not clear if the carb dip cannot flow into it. Ultrasonic does nothing to clear a plugged passage. Blow them all out with compressed air.

Your bike looks great BTW. Love the chrome and shiny parts.

Agreed, a VERY nice looking bike.

Rick H.

SUCCESS !!! ....pilot jet for the #3 carb is clogged, and solidly clogged at that .....using teeny gage wire of 3 sizes and stripped bread bag tie, cannot dislodged the deposit in the main passage of the jet (pulled the other 3 pilot jets to confirm you can see right thru them and blow compressed air thru them: yes, I can) ....going to soak it in solvent for a bit to loosen things up and that should do it guys .....I'll report back, and thank you all for the ongoing in-line 4 education

Before you put all carb parts together again check your air bleeder tubes, (#9 in the diagram) for clogged passage.

yessir, all bleeder ports on all pilots clean as whistle .....all back together now, first restart as soon as I pop a celebratory cold beer ! ....

I will toast with German beer, Prost!!!

here she is, loud & clear on all 4 ....THANK YOU all for the assists !

Starting with a light touch of the Botton and sounds great, thumbs up!!!

Sounds great . Nice bike