Idles fine dies with throttle

Streaker

Streaker

New Member
I've got a 77 cb750 and when I fire it up it idles. As soon as I touch the throttle it dies. From what I've read the pilot jets are the problem. I've cleaned those things twice with carb cleaner and an air compressor. I've gotten pretty far using the search button but they all say the same thing. Anything im missing? Thanks for your time
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For every action there is a reaction
 
Did you COMPLETELY disassemble the carbs? (all jets, emulsion tubes etc, etc, etc) If not. that is your problem. You cannot just squirt solvent through the jets, you must break the carb bodies down to JUST the body and clean it passageway by passageway. Once you understand what each passageway does, then you will be able to know for certain that it is clean and working properly. Then clean and inspect each part one by one and re-assemble as you go.
 
Thanks jp for the prompt. Well I tore everything apart and made sure everything is clean and clear. Now it just boggs down when I turn the throttle so that's better then dying. So I guess I need to adjust each fuel screw? I have them at 1 1/2 turns.

For every action there is a reaction
 
Sounds like it has not been mechanically synced. Make sure the slides are all the same height, and try again.

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I´ve had the same problem with my KZ400.

It came down to bench syncing the carbs and using a manometer later to fine tune the idle.Hope its just that man.
 
Ryan Stecken said:
I´ve had the same problem with my KZ400.

It came down to bench syncing the carbs and using a manometer later to fine tune the idle.Hope its just that man.
Click to expand...
His symptoms are the exact same as I had on my KZ650. Simple mechanical bench sync had it running well.

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Re: Idles fine dies with throttle

Any better ways to get that plastic piece besides drilling a hole inserting a screw and pulling it out?

For every action there is a reaction
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Nevermind. It is!
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Well I tore the carbs completely apart and cleaned everything. As shown in the pics above I took apart the accelerator pump and cleaned that. Bench synced the carbs. Still bogs down when I throttle. The rpms fluctuate and sometimes stay high or take a long time to come back down. I checked the cables and everything snaps back into place. I've played with turning the fuel screws from 1 1/2 to 2 turns out. Maybe the float needles are stuck. Idk
 
Tune-A-Fish said:
Leaky boots spray carb cleaner around the boots and see if you have a leak
Click to expand...
Funny you should say that. I was just watching a video about that. Thank you sir
 
It could be down to a damn load of things.Check your plug caps.My KZ400 had the black NGK plug caps and one was so old it had a crack in it, when I pulled it off it cracked and suddenly the problem was solved.
 
have you checked each cylinder is firing do you have a infa red thermometer ?

if one coil is dropping out you can have the same reaction and it not be carbs
 
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Well after starting a new job I some time to put new intake boots on and it idles much better. Still bogging when I hit the thottle. I'm going to turn my screws out to 1 1/2 from 1 1/4 see if that will change anything. As well as checking my sparkplug to see if they are black or wet.

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