Two '75 KZ400's, low $, and a need for cheap speed

Hey all,

I am the proud owner of 2 1975 kz400's. One is a strong runner, with a newly cleaned and jetted carb, pod cleaners, 2-1 exhaust, hi-flow muffler, clean fluids, straight lightened frame and 19,xxx on the odo.

She has some mean blow-by, a new knock on the right side, and the old clutch is fading fast.

The other is a donor/practice bike which I've already scavenged cables, lights, wires, seat and ignition coil from. She's there mostly to see what I'll see when I do the real overhauling.

The runner is ready for new gaskets, rings and seals, and while I'm in there, I want to do what I can to make her better, stronger, faster, w/out spending $6 million.

If you have any tips or secrets, or general knowledge, please enlighten me. I have gas engine experience, but I am a newbie to kawi bikes in general.

Thanks for your help!

Carbs. Cleaned and jetted carbs. 2 of 'em. Sorry.

swap in a 440,direct replacement

try kz400.com

Thanks, Rex. Any suggestions on if I wanna keep it a 400?

mill the head,mine was milled.025 and 1194 for a base gasket(required to use base gasket on 400 because of the oiling system) which bring comp. ratio to 10.8 on a 440.smooth out any rough edges in the ports,valve and port size are plenty big allready.othre wise just good ring and valve seal.and sounds like rod bearings

That's awesome, Rex. Thanks.

I'm def gonna seat the valves and replace any worn or failing parts in the valvetrain, and was thinkin about boring it .5mm over, cuz I have xtra pistons that size anyway. Any idea how that'd work out, with shaving the head?

Or is it better to mill the head & keep the old pistons if theyre not too worn out?

fresh straight cylinders are better,i think Z1 Ent. has rings,watch the dome height,some are different sizes

Thanks, Rex! You've been very helpful! I'll keep posting as I go thru the overhaul!