KZR's Bikes of the Month for 2024

Jetting after a rebuild

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29 Jul 2023 13:54 #887710 by kzken750
Jetting after a rebuild was created by kzken750
I have just rebuilt my kz750 with a wiseco piston kit bringing it to 810cc. The bike stock has a #125 secondary jet. Before the rebuild and with the 4 into 1 Yoshimura pipe I had boosted the jet to #130. With the larger pistons from the rebuild I went up again to #142.5. The bike seems to be starving for gas and the spark plugs are whiteish. How far up should I go with the jet size?

thanks

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29 Jul 2023 15:38 #887713 by Nessism
Replied by Nessism on topic Jetting after a rebuild
I don't know what to say about jetting other than Dynojet.

That bike sure looks nice!  Love how tight the pipe tucks up tight to the sump.  
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29 Jul 2023 15:51 #887715 by Scirocco
Replied by Scirocco on topic Jetting after a rebuild
Don´t forget to went up with the pilot jets.
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31 Jul 2023 06:09 #887747 by Beaner242
Replied by Beaner242 on topic Jetting after a rebuild
Yes. When are you checking the plugs?  You may be jetting the main when you need bigger pilots. 

1982 KZ1000K LTD Chopper
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31 Jul 2023 11:09 - 31 Jul 2023 11:15 #887749 by Nessism
Replied by Nessism on topic Jetting after a rebuild
The Keihin CV34 carbs, as used on this bike, have both a primary and secondary main jet.  

The Dynojet kit comes with new secondary main jets and new needles.  They don't mess with the primary main jet, or the pilots.

www.dynojet.com/amfile/file/download/file/558/product/3255/
Last edit: 31 Jul 2023 11:15 by Nessism.
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03 Aug 2023 06:08 #887890 by kzken750
Replied by kzken750 on topic Jetting after a rebuild
bigger pilot jets are on the way. Also going up to #150 on the mains. I got advice at first that I did not need bigger pilot jets. I hope this will do it. thanks

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