TOPIC:

This 1976[date of manufacture on front fork] KZ650 is starting to frey 'me' nerves. I recently replaced the cyl. head c/w new gasket,new points and condensers with the hope of at least some type of idle speed. It will start every time you spray a small amt. of gas in the carb intakes, burn it and die out. Sometimes it will keep running for 10 to 15secs. with the choke almost on, or alternating your hand over the carb intakes. It seems to me the clys.are starving for gas,or I have a vacuum leak. I see on this site members talking about vacuum hoses, but I can't see any place on the carbs for a hose connection, only the four small ones on the bottom of each carb. I do notice the fuel line from the tank,going into a tee and then into the carbs is loose,move forward and back, but no gas leak is visable there. I set the four screws on the bottom of the carbs two and half turns. Is this correct? Any advice sure appreciated. O ME NERVES! Newfie saying!

sounds like it might be the low speed circuit in your carbs. that means the air screw and the air passages that lead to the pilot jet. the jets could be clogged or the passages. i'd suggest thorough carb cleaning. or at least blow out the jets and air passages and drain float bowls.

taking all this stuff off when you did the work could've stirred up some crud that was sitting dormant on bottom of tank or float bowls

I agree. Old bikes collect crud. It seems to lay dormant just up until the time that you try to improve something, then it breaks lose and fouls stuff up.

Idle speed would seem to come from the carbs more than the head and spark. Had you considered rebuilding the carbs? Or at least cleaning the suckers out?

My 77 idled at 2200 when I first got it. Now I have it down to 900 but it took a lot of potentially frustrating work. Older bikes need attention. Know this.

Get the manual for reference, find some archived "carb rebuild" posts, get yourself a lot of beer and about 15 free hours if you've not done it before.

There is a lot of help available here for this project, many who thought they could not, have been able to.

I did.

I would turn those screws back and just clean the carbs. The T setup you speak of on the carburetor fron the tank sounds pretty confusing to me. The T is not your fuel line my friend, I may be wrong but if the 650 carb setup hasn't changed throught the years from 76 to 78 I would say you are mistaken. The T connection you are seeing is possible your vacuum lines and thats why they probably don't leak fuel. Your fuel line should be one fat hose from the tank going between your no.2 and 3 carbs. If you can take a pic or draw out what you see that would be much appreciated.

The "T" is the center fuel passage connector for the four carbs. The manual calls it a "Three-way fuel joint."

Four carbs, three junctions, each of the three pieces has 4 o-rings by the way, connecting the fuel passage to each of the carbs. the center one has a "T" fitting to allow the fuel line from the petcock something to terminate to. It does turn axially forward and backward as well.

The hose fittings on the bottoms of the carbs are used for carb synching. Check that they are not cracked and/or leaking at this point.

My manual says to turn in the screw on the bottom until it lightly seats, then back it out one and one eighth turn (1-1/8). At that point, there might be plastic limitor caps that restrict the range of rotation to about an eighth turn either way.

It makes sense that you have turned it out more than the manual states as you are trying to get more gas into the engine. But there seem to be other problems that this screw should not be compensating for. Know what I mean?

If it were my bike, I would seriously consider carb cleaning at least.