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Carbs wont sync

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Burningrubber

Carbs wont sync

Im trying to sync my carbs on my 1976 cb750f
Everytime i adjust one the others change and the idle goes high
Anyone know what this might be
I included a pic of what synchronizer im using

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Re: Carbs wont sync

Administrator

I am assuming you are adjusting the with the throttle adjustment on the top of the carbs. I have seen guys trying to sync carbs with the pilot screw, and that is not what does it. The idle does increase as the carbs come into sync. As this happens, you should be able to bring it down with the main idle adjustment knob. You could have a vacuum leak causing this. Also, are you blipping the throttle after each adjustment?
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1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
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Burningrubber

Re: Carbs wont sync

Yep im adjusting using the top throttle adjuster
I dont think its a vacuum leak as i replaced the intake boots and made sure the where on correctly, do i have to adjust the idle screw as im syncing ( the small ones on each carb right?)

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Re: Carbs wont sync

Administrator

No, the big one that adjusts the idle. When you sync the carbs, what you are doing is adjusting the idle on each carb, so that they are all drawing the same vacuum. When done, they should be around 7inches of vacuum. And the idle should be around 1100 RPM.
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