Faded Glory - 75' KZ400S

It still happens to some of us old-timers. I was working on my cafe bike (XS650) and drained the tank to repair the petcocks. Put it all back together with a little bit of fuel JIC. Went down the road and all was well. Flash forward a few weeks and I'm heading to Bike Night when the bike starts to run crappy. I checked the odo and it showed 16 miles so tank was full. Made it there and back but it kept stalling on me. Laying awake that night imagining the worse I suddenly remembered I never put the gas back in. Filled it up and all is well. 

So this weekend was a complete wash...
Ultimately i ended up with a bike that no longer starts.  /Facepalm

Pulled the plugs, definitely running too rich

Removed one shim from the needle as reccomended in the 6sigma documentation (too rich midrange)
went for a quick ride, but it was running really rough, so i decided to check the points and valve clearances before messing with the carbs too much more...

i cleaned/checked gap on the points, adjusted the valve clearances...

I gotta say, adjusting the valve clearance is a real PITA...  not nearly as bad as the whole shim setup on my XS1100, but still.
not having a lift table, requires contorting your body into positions i'm getting too old to perform.
blindly thrusting into the hole easily (pun intended) takes several attempts before success...
get the gap set perfectly, but once the lock nut is set, the clearance ends up being too tight or too loose...

had to play a game of trial and error.  leave the feeler in place, lock the nut, check, then make micro adjustments until it feels right.
again, PITA.

Also, it seems I need new gaskets for the timing cover, and both of the valve adjustment covers, the latter is dripping oil onto the plugs.
Anyone got a lead?  Z1 doesn't seem to have them

The other thing i addressed has been bugging me since i bought the bike.
both of the positive wires coming from the battery, had un-insulated spade connectors rattling around, just looking for a ground...

One goes to the fuse that feeds the ignition switch, the other goes to the voltage rectifier.
replaced with bullets i had laying around.  nothing special.

during the process, i lost my balance and accidentally tugged on the wire from the rectifier, and it folded the connection on the back.  oops!
i bent it back, but i'm afraid i may have damaged it.

At this point, i have power when the key is turned on, but the bike won't start.
i pulled a plug, but it's hard to check for a spark when kicking the bike, so i'll have to figure something out.

some time this week, i'll have to dig back in, and re-check the gap on the points.
worse case scenario, i'll pull the rectifier from the parts bike, and give that a shot.

Two steps forward, right?  /Shrug

I think the timing cover is #14050-10 and seems nonexistent, but it's pretty simple, so you could make a new one from bulk gasket paper - might be able to find some at your local parts store.

Valve adjustment covers I think are 11023-007 and you can find some replacements to buy for not much money - but you could probably make those too if you go the DIY route. 

Hope I identified the covers right, I'm not familiar with your bike 

I really enjoyed reading this thread. My second street bike, at age 17, was the red 1975 KZ400. I loved that bike, but at 17, I drove the crap out of it. (Raced it hard, laid it down, hit a car, blew an engine, bought a parts bike, kept it going......)
Last winter I found an old H1E and did a complete frame up restoration on it, drove it a bit and sold it. What a great Covid isolation winter project. 
Afterwards I wanted to find a KZ400 to restore this winter. I didn't find one but I did find an 81 KZ440C. Another great find and another great winter project. Hoping to have it all reassembled in a few weeks and ready to ride. I hope I don't have the tuning issues that you have run into. However, when I rebuilt the carbs, both idle/air screws were seized and broken by a PO. I ran carb cleaner through all the orifices and ports hoping that the factory set idle/air mixtures screws were still in that set position. Time will tell.