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I am restoring a 1980 Kaw Kz750 Twin and have run into a dead end. All is done on the bike BUT, here comes the part where I need someone's input. I'm sure it's something very simple but my frustration has caused it to appear more complicated!! My problem is that I can't get a good spark to the plugs. The bike will idle with the choke on ONLY. The minute you open the throttle, it dies! I've changed the coils, tried 3 coils that I know work and to no avail. Carbs are rebuilt. Has new points and plugs. Wires are good. Has new battery, new starter solenoid, and wiring harness is just fine. Can anyone help?? What could be the cause? Sure appreciate what you can offer. Thanx

Maybe some of these guys can help, some of the members are from right here in the states: http://www.lonesometwin.co.uk

Only idles on choke.... dies with throttle.... the carbs may have been rebuilt, but they are still not working right. I'd guess that it's not getting enough fuel, might still have some clogged jets or passages.

Thanx for the links, nothing really there. I have used an air compressor and blew out all the jets, soaked them with carb cleaner, and the float bowls are filling and all seems to be in order there. I still have a weak spark so, do you all feel it is still in the carbs? I am so frustrated that I am standing here, one foot away, with a lighted match. Help!!!

Did you go to the lonesometwin link ? You can ask those guys the same questions as a visitor, they know the 750 Kaws. If you want the answer, ask the KZ750 experts. XS

I also think the problem is in the fuel delivery. Carbs or fuel line from tank.

If the carbs have anything more than a light build-up of gummy varnish, carb cleaner and air probably won't get it. Varnish gets very stubborn in a short time, and needs manual removal or an ultra-sonic cleaning.

Choking it should not affect weak spark. I don't think ignition is your problem right now....

check to make sure the carbs have the correct jetting, the bike is old and someone may have thought that they knew how to rejet carbs

I have cleaned the carbs 3X's. I ate my spaghetti out of one of the bowls!! LOL Anyway, there is no gummy residue at all. If the screw out of the bottom of the float bowl and gas flows freely, then it's not starving for fuel, right? I soaked them overnight in carb cleaner so I know they are clean. Now, as far as checking to see if jets are the correct ones, maybe I should try that. I know they are clean because I used canned air on them after cleaning them. I looked in my manual and it says to adjust the pilot screw out 1-1/2 turns but, I can't find the pilot screws!! I can find where they are suppose to be but there is a plug there. If I pop out the plug and there is no screw, then they will leak and I will have to replug the hole again. How can I know if there is a pilot screw without taking out the plug. Also, FYI, it came with those plugs in so I'm just going by what I am finding there. Thanx so much for all your help......my life and my bikes future is in your hands. Ohhh, and since I am getting such wonderful advice, I blew out the flame that I was going to torch the bike with!!

On another website, condensors was mentioned. Any comments? Also, yes I checked out the links and one of them only had comments by one person and nobody else. I'll go check again. I'm going to first look in my manual and see what it says about the condensors. Let me know if any of you have a comment on this. Thanx again!! Tell ya what.....if I git this bike running after all your help.....well, guess I owe ya a cold one or whatever ya drink!!!