1978 Kawasaki KZ650C Mikuni Mixture

A reader seeks advice on setting the mixture on the Mikuni carburetors on his Kawasaki KZ650C.

Reader Contribution by Brian Rhenlun
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by Keith Fellenstein

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Mikuni mixture

Q:I could use some help setting the mixture on my carburetors for my 1978 Kawasaki KZ650C. How many turns out on the air/fuel mixture screw do you go to adjust a Mikuni carb? Remember there are four carbs on this bike.

Brian Rhenlun/via email

A: It’s almost universal that idle mixture screws are set at 1.5 turns from gently closed. Start there and turn them all out 1/2 turn and see if the idle speeds up. If it does, go a further 1/2 and check again. If no improvement try a 1/2 turn in from your start position and do the same test. Once you have figured out the right direction, fine tune in 1/4 turn increments. Once you have the fastest idle, use the idle speed screw that controls all four carburetors at once to set the correct speed. After that you may need to go back and double check the mixture. It can take a while to get it just right.

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