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I have a 78 KZ650C2 with pods,4-1 header. Rest of engine is stock, Im at 4,500 feet above sea level, plugs were very sooty before I changed the needle setting and jet size to 92.5 . Im interested in what jet size would be correct for my mods and altitude ? I'll get into my timing settings later, when I do the wiring to coil upgrade and add the new ignition set up . Thanks Wayne

Wayne, I have to agree with your Clymer, Kaw Factory Service Manual and Haynes for your bike. Get the ignition right before worrying about jetting. Check the timing and make sure your spark is good BEFORE taking on jetting. You can't rejet away ignition issues.

I have a 78 650C and also live at 4500 feet. before I put in the big bore kit my bike was set up just like yours. 4-1 pipe and pods.
You need to make sure your ignition is set up correctly. I installed the Dyna S ignition years ago and glad I did. Well back to the jetting.
I had 118 mains, #15 pilot jet, needle in the middle position and the air screw turned out 1 1/2 turns. This gave me perfect jetting. This gave my plugs the perfect tan color and it ran fantastic.