no spark at all on all 4 cyls 1975 z1

i recently had to work on my tach and dropped a piece that i thought went under the tank.it wasnt now with a new battery it turns over very good but no spark.when i slid the tank back some could i have unplugged something? i also had the head lite out also.any ignition wires in there? the bike ran great untill i replaces the tach lite bulb,,,,tia,,,,rick

In an original harness the coils are powered by a yellow with red wire from the kill switch to the coils.
(also look to see if the kill switch is off or on, haha)
Once you figure out what the problem was, I would recommend adding the "wired george relay" to the coil circuitry. But solve your no power issue first.

There's not "directly" any ignition wires within the headlight bucket but there is the power source for ignition there. The Brown wire coming off the 4-pin ignition switch routes to your RH switchblock, this is the + and goes directly to the upper portion/half of casting or ON/OFF/ON selector knob. The half moon looking brass, 2 spring loaded, piece slides across the two contacts on ramp plate. This half moon brass contact disperses + to the starter and coils. So in theory if Your starter functions then you "should" have + power to your coils via that Yellow/Red double female connector underneath the tank. Double female 4mm terminals btw. One for each source + per coil. Coils can pull a bit of power and if that mentioned "half moon" plate isn't nice and clean then the supply "can" be spotty and intermittent/weak. That's why it was mentioned about the "wired George relay" thingy. I've actually never have seen a real reason for it because i go thru ALL the switches initially as to deter any voltage drop anyway and have never had a problem. But persons do it to compensate for weak links? Check supply at that double female for positive to ground and note any funky behavior and tightness of the bullet connectors when inserted. A couple photos of front/back of your switch if proper 1975, they only used that upper casting in 75. The earlier Z 1972-1974 shown right above it in photo.    Engine Stop Yellow font on the bottom and what to expect if you're cleaning it. Have Fun, Clay    

Sf4T7, starter won't start if in the OFF position, designed that way. But You knew that ha. 

Hey Asphalt, I just went and tried it and you're right!  I guess in 45 years of owning my Z1 I never tried it!  Or maybe I knew it and it's buried in the 70 years worth of unrelated info clogging my brain, haha  

Don't Even thinking about "unclogging" the grey mass SF!! Therein contains all the relevant crap we know and all those life's experiences!  A lobotomy costs too much anyway and probably not covered under Medicare/Medicaid plan anyway, haha. At least not at an "elective" level.    

the kill switch on the handle bar works as it should. with the the switch off the engine will not turn over and will with the switch turned on..still no fire to the plugs
 

Correct..that was duly noted initally. Now go grab Your VOM and check some stuff already. You want to check the double female terminal right next to your 3-Pin outage block. If power is coming out and male terminals properly connected then your points or coils went south. Hopefully You didn't hook-up a charger or ill "jump" your system from a non-suitable power source? Also check your Black/Yellow ground wire running from your harness to the negative "big" battery black wire. Really can't hope it to run from here you need to do some checking first!   

Clay I see your meter is "period correct" for the stuff you are working on - Lol 

Clay, I wouldn't dream of changing any grey gooey mass.  It's what makes me the charming intelligent pig headed piece of work that I've become!  hehe   

problem solved!!!!!   when i changed out the batter there was a small black and red wire (not the main wires) which i assumed was to a battery tender that i never used so i never hooked up the black wire. i followed up and it went up into the wiring harness. when i hooked it it and hit the starter it fired right up.thanks for all the help guys....hydro

See!! Often the overlooked crap, just have to remember where your fingers traveled previously, ha. Great to hear!! Another beast on the road, unless it's too cold, hehe. SF i totally believe You're an intellect with all Your natural flowing locks of hair! I can't say the same, my follicles have given-up but have found patches of hair in various spots that shouldn't be there? Wookie..what can i say, i'm oldtimey and wouldn't trade my analog meter for the fanciest Fluke ever produced. I can see/read my meter in real time instead of an ever changing LCD display bouncing around. If i wanted real time in scope display id pull out my oscilloscope!