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KZ900A4 Blowing Fuses

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BigZCas
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KZ900A4 Blowing Fuses

#1 PostAuthor: BigZCas » Thu Aug 23, 2018 2:32 pm

Could anyone advise please ?
Just finished wiring the Z900a4 restoration and I have a problem, when I switch the ignition on the idiot lights are dull before fading off due to the 20amp fuse blowing.
There has been a conversion as the white plug is missing.
When i took photo's as I stripped the bike, this area was taped up so just cant see how the shinny new white wire and the old white + red/white went together ?? :??
I think this is where the problem is as all other is the same as it came off...
I did not want to guess as I might cause some damage.
Can anyone help out please :??
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Past 5 Years
1974 UK Z1a, Candy Tone Brown/Orange
1976 KZ900a4, Diamond Dark Green
1978 KZ1000a2, Luminous Green
1976 KZ1000a1, Red
1972 GT750J, Candy Lavender

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z1bman
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Re: KZ900A4 Blowing Fuses

#2 PostAuthor: z1bman » Thu Aug 23, 2018 6:46 pm

idiot lights shouldn't blow the 20 amp fuse they are wired to the 10 amp fuses

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BigZCas
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Re: KZ900A4 Blowing Fuses

#3 PostAuthor: BigZCas » Thu Aug 23, 2018 7:16 pm

OK, i've investigated further.
Note: I have no pipes on the bike and so the bike is not running,all was fine before the strip down.
When I switch the ignition on with the Kill switch in the off position everything works fine (lights,stop light,indicators,horn etc etc
But has soon has I turn the kill switch to run the idiot lights dull right down and then after about 4 seconds the 20 amp fuse blows.
I have tried disconnecting the red/yellow wires to the coils but no difference.
Also disconnect started motor wire from the solenoid no difference.
Any ideas / tests that I could do, any advice appreciated... :?? :??
Thanks
Cas
Past 5 Years
1974 UK Z1a, Candy Tone Brown/Orange
1976 KZ900a4, Diamond Dark Green
1978 KZ1000a2, Luminous Green
1976 KZ1000a1, Red
1972 GT750J, Candy Lavender

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Re: KZ900A4 Blowing Fuses

#4 PostAuthor: Philippe » Thu Aug 23, 2018 7:32 pm

Hi Cas
try to disconnect the right hand handle bar switch. If everything is OK I guess the problem is in there or in the wiring coming from the switch to the main loom.
Did you check the starter solenoid? Is the wiring OK? The black wire that runs from the solenoid should be connected to the black wire from the main loom. It's no earth wire! The negative ground wires are black/yellow. The black wire activates the solenoid and the current comes from the starter button.
Look at a picture of the wiring of your bike, check if the connections are OK.
Electricity... a strange thing you know!
Good luck
Philippe
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Re: KZ900A4 Blowing Fuses

#5 PostAuthor: BigZCas » Thu Aug 23, 2018 7:47 pm

Hello Philippe,
If I hold the switch in my hand everything is fine but i guess this is because the kill switch earths through the handlebars hence it is not making a circuit when the switch is not clamped to the bars.
Could a duff solenoid cause this ?
Thanks for helping
Past 5 Years
1974 UK Z1a, Candy Tone Brown/Orange
1976 KZ900a4, Diamond Dark Green
1978 KZ1000a2, Luminous Green
1976 KZ1000a1, Red
1972 GT750J, Candy Lavender

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Re: KZ900A4 Blowing Fuses

#6 PostAuthor: DavidZ1R » Thu Aug 23, 2018 8:01 pm

Should the white wire coming from behind the solonoid not fit into the double joint and that white wire connect to the other free one, I have done a rec reg conversion on my z1000a1, the wire schematics show the same, my conversion is on the white plug
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Re: KZ900A4 Blowing Fuses

#7 PostAuthor: DavidZ1R » Thu Aug 23, 2018 8:05 pm

Ignore the yellow wiring on the white plug, I reused the plug and jointed the wires.
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Re: KZ900A4 Blowing Fuses

#8 PostAuthor: BigZCas » Thu Aug 23, 2018 8:41 pm

Hello David,
I can t quiet make your photo out ?
It looks like you have 2 white wires going in and 2 coming out of the LH connector ?
Cheers Cas
Past 5 Years
1974 UK Z1a, Candy Tone Brown/Orange
1976 KZ900a4, Diamond Dark Green
1978 KZ1000a2, Luminous Green
1976 KZ1000a1, Red
1972 GT750J, Candy Lavender

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Re: KZ900A4 Blowing Fuses

#9 PostAuthor: z1bman » Thu Aug 23, 2018 8:48 pm

with the switch attached to the handlebars disconnect the the block connector & with your multi meter set to ohms check the brown. black & yellow/red kill switch in the run position to make sure they do not go to earth

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Re: KZ900A4 Blowing Fuses

#10 PostAuthor: z1bman » Thu Aug 23, 2018 8:57 pm

DavidZ1R wrote:Should the white wire coming from behind the solonoid not fit into the double joint and that white wire connect to the other free one, I have done a rec reg conversion on my z1000a1, the wire schematics show the same, my conversion is on the white plug


looking at this photo what does the green wire with a red trace go to? as it looks like it is plugged into the black wire going to the solenoid ?

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Re: KZ900A4 Blowing Fuses

#11 PostAuthor: DavidZ1R » Thu Aug 23, 2018 9:23 pm

z1bman wrote:
DavidZ1R wrote:Should the white wire coming from behind the solonoid not fit into the double joint and that white wire connect to the other free one, I have done a rec reg conversion on my z1000a1, the wire schematics show the same, my conversion is on the white plug


looking at this photo what does the green wire with a red trace go to? as it looks like it is plugged into the black wire going to the solenoid ?


I bought a rec reg off eBay as was suggested by Pauljauque, it was cheaper than a bona fide replacement so I thought I would give it a go, the old reg had failed so tried it. The two greens if I remember where earth's, two reds live feed, I have done about 500 miles with it, it produces 14.5 v at the battery. If it fails I will just have to buy a genuine one, but hey Ho for now :D
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Re: KZ900A4 Blowing Fuses

#12 PostAuthor: DavidZ1R » Thu Aug 23, 2018 9:26 pm

BigZCas wrote:Hello David,
I can t quiet make your photo out ?
It looks like you have 2 white wires going in and 2 coming out of the LH connector ?
Cheers Cas


I will take a clearer picture tomorrow.
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Re: KZ900A4 Blowing Fuses

#13 PostAuthor: ZedHead » Fri Aug 24, 2018 7:18 am

Steve, How did you get on investigating the switch?

The fact that everything works when you remove the switch from the handlebars would suggest the switch is shorting to the bars, possibly through the switch housing. If it was the solenoid removing the switch would make no difference.

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Re: KZ900A4 Blowing Fuses

#14 PostAuthor: ZedHead » Fri Aug 24, 2018 9:07 am

IMG_2794.JPG


Looking at the picture, I would say the screw mounting the red/yellow wire is shorting to the switch body. Which, is shorting to earth through the handlebars when the switch is mounted to the bike. This is why it works ok when the switch is removed from the bars.

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Re: KZ900A4 Blowing Fuses

#15 PostAuthor: DavidZ1R » Fri Aug 24, 2018 6:01 pm

Think you have the white wires wrong, you should have the white feed from the battery with the double joint, into that goes white/red wire from the fuse box, and the white wire from behind the solonoid into the double joint, the other goes to the white feed wire from the reg / rec, that's how mine goes, no problems
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