76 KZ900 Rejetting

All,

I've searched, and apologize for asking a question that I'm sure has been asked before, but here goes: my 76 KZ900A4 came to me with K&N pods and I hoped it'd been rejetted. It hasn't. Stock 115 main jets are still in there. I know it'll be trial and error to get it right, but in case she runs lean, I'd like to have a couple more sizes on hand to try. So should I get 120 and 125? 117.5 and 120? I'm still in the process of cleaning up the carbs and will sync them etc...and I know I'll likely have to adjust the air screw and e-clip on the needle, too. Anybody have experience that'll help me out?

Thanks!
Chris

hopefully wiredgeorge will respond.....he can get you dialed in....i ran my numbers by him for jetting a 78 1000 with a pipe and pods.....he was right on..check out his site......just google his name....keith

Hello, Chris, and WELCOME to KZR forum! We're glad you're here!

Stock KZ900 carbs (Mikuni 26mm manual slide) are very user-friendly, and may perform just fine using K&N pods with stock jetting, even with 4>1 exhaust.

How do the sparkplugs look now?

If in doubt, would perform plug reading after high speed throttle/ignition chop for visual evidence of what's happening inside the combustion chamber attributable to main jet size. If plugs are a nice tan color, would leave the jetting alone.

Good Luck!

P.S. And don't mess with the jet needle clip positions. Leave them in the middle slot as God and MaKaw intended. :lol:

If not already done, would assure ignition components are up to snuff (look for properly timed good fat blue spark, with correct advancer function). And perform compression test (remember to hold throttle wide open when testing) and assure valve clearances are set to specs. And assure ample clean uninterrupted fuel supply to carbs, with an in-line fuel filter. And of course also check service floatbowl fuel levels (using clear tube test method).

Even perfect as-new carbs depend on all the non-carb components, and can't compensate for faults in the other areas.

Thanks for the info, guys. I've checked out WG's site and done his coil mod already. Prior to that, plugs were sooty very quickly after putting them in, which surprised me as I didn't expect a rich mixture. I've verified I have stock 17.5 pilots as well. Hopefully will have the time to put the well cleaned carbs back together and sync 'em next Tuesday. My exhaust is a 4 into 2 megaphone that I don't think is stock...we'll see how it goes. Riding season is almost over up here, so if it doesn't work just right right away it's not a big deal, but I'd like it if it did. Only 4k miles on her