- Posts: 13
- Thank you received: 0
1979 kz750 twin Wiring Nightmare
- Berserker
- Topic Author
- Offline
- User
I replaced the petcock and fuel lines, a new fuse box, got a new battery and confirmed the headlight does work directly to the battery but none of the wiring harness gives me any confidence in this bike. And this is my first bike. Electrical isnt too new to me as I used to be a guitar tech but, ignition systems arent my specialty. I have a spdt three tab on off switch I bought in case someone could explain how to get that wired in just to start it and test the engine before throwing any real money at this bike. The wiring schematic is perhaps the least impressive aspect of this service manual to me, so I can use any help possible. Thank you all.
Please Log in or Create an account to join the conversation.
- Rockybalboba
- Offline
- User
- Posts: 34
- Thank you received: 4
kzrider.com/forum/4-electrical/172746-19...mattylight?start=200
Do you have a service manual and multimeter?
Please Log in or Create an account to join the conversation.
- Berserker
- Topic Author
- Offline
- User
- Posts: 13
- Thank you received: 0
Please Log in or Create an account to join the conversation.
- loudhvx
- Offline
- KZr Legend
- Posts: 10868
- Thank you received: 1616
www.kzrider.com/forum/4-electrical/17274...ght?start=200#463164
That should make it self explanatory how to install a generic switch. It is drawn showing the original switch modified to simply be an on/off switch, but you can just replace it with a simple toggle switch.
All you really need to make it run, temporarily, is the ignition system which is a basic points system. It can be done with one or two wires total from the battery... assuming you can kick-start it.
1981 KZ550 D1 gpz.
Kz550 valve train warning.
Other links.
Please Log in or Create an account to join the conversation.
- Berserker
- Topic Author
- Offline
- User
- Posts: 13
- Thank you received: 0
Please Log in or Create an account to join the conversation.
- loudhvx
- Offline
- KZr Legend
- Posts: 10868
- Thank you received: 1616
That makes it a 78 Kz750B3 twin.Berserker wrote: It turns out my bike is a 78 750B. Is the wiring still the same?
The ignition switch wiring is a tiny bit different from the 79 Kz750B4 twin.
(I'm writing out the long designations so people viewing later won't get confused mixing up models.)
You can use the same drawing with a couple minor differences.
Just ignore the yellow wire on the ignition switch in the drawing.
The wire feeding the kill switch will be brown on the 78 B3 instead of yellow on the 79 B4.
Here's a 78 B3 diagram. It includes the electric start.
But you can use it to compare the differences between the 78 and 79 ignition switch.
(I realize you have an aftermarket switch so the factory switch wiring is not very critical for you.)
www.kzrider.com/forum/4-electrical/17274...ght?start=280#579749
Regarding switches. You should know not to use any cheap switches that are made with vinyl. They love to melt in the on position.
Use a metal switch if you can find a good one. Most are cheap and get flakey soon. Or you can get a heavy duty, high quality switch made of epoxy resin that will last many years, but they are not cheap.
Your best bet is to probably ohm-out the ignition switch you bought and figure out how to use that as an on-off switch.
1981 KZ550 D1 gpz.
Kz550 valve train warning.
Other links.
Please Log in or Create an account to join the conversation.
- Berserker
- Topic Author
- Offline
- User
- Posts: 13
- Thank you received: 0
Please Log in or Create an account to join the conversation.
- loudhvx
- Offline
- KZr Legend
- Posts: 10868
- Thank you received: 1616
The ones designed specifically for KZ's are better, but they don't all mate up to every model. If you can find one that fits, I'd recommend that and splice the wires if you have to .
Simple toggles should be the decent epoxy or metal ones. Pot metal is ok, as long as the switch is manufactured decently.
You'd probably spend $20 or so through a reputable supplier like Digikey for a really good 20 amp toggle switch.
1981 KZ550 D1 gpz.
Kz550 valve train warning.
Other links.
Please Log in or Create an account to join the conversation.
- martin_csr
- Offline
- User
- Posts: 8068
- Thank you received: 1656
Z1Ent >> 1978 KZ750-B3 >> Emgo ignition switch 40-80600
...
Please Log in or Create an account to join the conversation.
- Berserker
- Topic Author
- Offline
- User
- Posts: 13
- Thank you received: 0
Please Log in or Create an account to join the conversation.
- Berserker
- Topic Author
- Offline
- User
- Posts: 13
- Thank you received: 0
Please Log in or Create an account to join the conversation.
- martin_csr
- Offline
- User
- Posts: 8068
- Thank you received: 1656
I would have thought the 6-pin would be a better match for a 5-wire ignition switch, but what do I know.
The B3 wiring diagram shows a 4-wire ignition switch, but the B4 is 5-wire.
Internet image searches = "KZ750-B3" wiring diagram & "KZ750-B4" wiring diagram.
....
Please Log in or Create an account to join the conversation.