TOPIC:

ok, long time since I've been in here guys! good to be back.

my old 1000ST just recently got a facelift, and when i put it back together, my starter switch is not working. So i went through the wiring harness at the front of the bike, and soldered the wires and covered them with heat shrink tubing. Didn't help. So, instead of trying to pull the wiring harness out, I installed a nifty little starter switch in the side cover on the left side. (Checked the solenoid, and it's fine) anyhoo, turns over now.
But now i have no spark. I found a black and a brown wire with blade connections loose under the tank. Don't know if these are ignition related or not. any ideas?

clutch switch have 2 black wires and will disable the starter and spark it is part of the saftey interlock system.

the brown is switched positive to something you need to check further

The black and brown wires may well be your horn wires. I am not sure if the ground on the ST is black or black/yellow. The brown hanging under the tank can't be many other things I can think of other than the horn.

As far as your problem, the power for both the COILS and the STARTER button are on the same wire coming into your right hand switch gear where they enter the kill switch. Open the kill switch and use a multimeter to figure out if you have power at the kill switch. I can't recall the wire color of the wire that is hot coming into the switch but you can see the yellow/red wire and black wire coming off. It will be the other wire. Possible blue, blue/white or brown?

Anyway, turn the key on and put your POS probe on the wire inside the kill switch and the NEG probe on a frame ground. You should have about 12VDC. Check for power on the other side... the yellow/red will go the coils and black will go down to the starter button.

As has been noted, the black goes through a safety switch on your clutch so make sure that the clutch safety switch isn't unplugged but since both the coils and starter button are not working, it sounds like a problem in the right switchgear where both of them share the same input to the kill switch. You might also make sure that the connector to from the right switchgear to the main harness is plugged in good because if it is loose, both the coils and starter button will not work.

you nailed it!

I got into it last night and it ended up being a loose connection on the yellow wire that runs to the switch on the handlebar. I rode for half an hour last night without any problem!

thanks a million!!!

Nathan, I have two project STs... One will be my personal ride bike and the other is the kid who works for me project bike. My bike is totally disassembled and I have completely restored almost everything and really only waiting on time to put it back together... I have some red paint that is the color of the 76 KZ900 LTD (base/clear type) but haven't done any body work or painting. I also am not clear how I am going to finish the engine. I am thinking of taking it and getting it bead blasted as the old black finish is ratty. How did you finish yours? Post some pics! BTW: It took me four hours going through my wiring harness and I cleaned every wire and connector and made a few repairs. I rewrapped the harness and also restored the switchgear and ignition switch and all that stuff took me most of a whole day!

There is a brown wire that runs to the break switch and a black wire that runs from the start button to the starter disconnect switch then to the starter relay