Wiring Issues

I have a 1981 kz750 just recently switched motors on it and was working on putting back together. i got it all wired up but i cant seem to get any spark or any lights to work. Everytime i turn the bike on the fuse with the white and red wire blows. Im not sure if i have it connected wrong. i have it going to the positve battery terminal. Im not sure what wires go to the postive battery terminal either. If you can post a pic to show me i would appreciate it. Also not sure why i am getting no spark and why the fuse keeps blowing. Maybe a short somewhere idk. Help Please

Likely something is shorted or pinched somewhere. Remove the fuse, and get a light bulb soldered up with two alligator clips. Clip the bulb in place of the fuse. The bulb will light up if there is a short, and will get dim or go out after you find and fix the short.

Any ideas where i should start to look. And would this cause me to get no spark as well

Any tricks to locate the short ?

Here's another version of Loudhvx's reply:

The Dreaded Shorting/Intermittent Electrical Problem!

Here is the most basic method I know(Taken from www.kzrider.com by member Patton)

1. Charge your battery and have it load tested if you can. The floating ball hydrometer can be used to check the specific gravity of the charged cells in the battery.

2. Disconnect the Black lead from the (-) Battery terminal... or Red from the (+) Battery terminal, it does not matter which one. Just 1, not both!

3. Connect one of the following test setups in series with the Battery terminal and lead:
3.1 A 12 V light bulb,
3.2 A 12 V test light,
3.3 A 12 V test buzzer or,
3.4 A 12 V horn... you get the idea.

4. With the Ignition Switch OFF, go through your harness and wiggle the wires while looking/listening for the test setup to go on/start buzzing.

5.With the Ignition Switch ON, repeat the test except this time the looking/listening for the test setup to go off/stop buzzing.

6. Be prepared to open the Ignition switch and check/test for solder joint failure and or circuit board micro breaks (don't ask how I know this ).

7. Be prepared to pull the wires out of the Head Light to test for failures at or near the grommet.

8. Be prepared to open the harness at or near the Steering Neck for failures. This is where wires tend to exhibit fatigue due to repetitive movement.

9. Be prepared to open the left and right switch gear to search for rust and or broken parts. CAUTION: watch out for flying springs, ball bearings and stuff. Do indoors on White sheet (again don't ask).

10. Be prepared to follow the heavy gauge wire from the Starter Solenoid (Relay) to the starter for bare wire exposure. Especially near bends and grommets.

11. If you can reproduce the fault symptom your are pretty much home free. Be prepare to find and repair/replace any internal wire breaks, insulation break downs, exposed wires, rubber grommet failures, etc. Often, shrink tubing will solve the problem temporarily until something better can be done.

12. I use a very good electrical contact cleaner/preservative called De-oxit made by Caig Labs in San Diego Ca. Their website is www.deoxit.com It can be purchased at Radio Shack and any other electronic supply store. I use it on all of my motorcycle’s electrical connectors , in my home entertainment center’s stereo patch cords and cordless phones charging cradles.

We could help better if we had a wiring diagram for your bike. Put your exact year and model in your signature, and we can check the filebase to see if your diagram is already posted on this site.

Basically you look at any area affected by your recent work.

It's also possible the reg/rec is simply shorted. That can cause the main fuse to blow. Are you using the original reg/rec? Did the bike work before?

If the main fuse blows, you won't get spark or light or much of anything working.

is the reg/rec the things the orange wires plug into

On-site wiring diagrams (see FILEBASE)

www.kzrider.com/filebase/doc_download/294-z750e2

www.kzrider.com/filebase/doc_download/295-z750h2

Including information about bike year and model is helpful to viewers and usually elicits better responses.
It's easy to put the information in your signature where it shows in all posted messages, past and future.
And may be changed whenever and as often as desired.
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Good Fortune!