TOPIC:

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

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.  

Don´t forget to went up with the pilot jets.

Yes. When are you checking the plugs?  You may be jetting the main when you need bigger pilots. 

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/

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