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Z1 Ignition circuit - burning fuse wire

Posted: Fri Sep 26, 2014 1:58 pm
Author: malmojoe
Hello, I have a new loom. Only have a new ignition switch and a new RH switch plugged in, so the bare minimum. As soon as I connect up the coils, the fuse wire starts cooking. Any ideas what is wrong?

Thanks for any help.

Posted: Fri Sep 26, 2014 4:03 pm
Author: z1bman
what size is the fuse? try fitting one coil at a time

Posted: Fri Sep 26, 2014 4:23 pm
Author: Mark Tiller
check all bullets....sounds like a dead short

Posted: Fri Sep 26, 2014 4:57 pm
Author: malmojoe
Using a 30a fuse, only other ones I have are 10 amp and blow
I have nothing plugged in except the ign and RH switch so no bullets.
Removing the rectifier and regulator from the circuit, and holding the white fuse wire onto the white feed wire, with both coils disconnected - no problem. No earthing, press starter - all good. If I touch the coil feed wire (yellow/red) with the coil wires, the coil with the closed points arcs and connecting it starts the fuse wire heating up.
Just to check the earths: battery earth cable is connected to engine, as is the earth from the regulator and the yellow/black wire from the loom.


Have checked the rectifier - OK
starter relay works and checks out (should there be continuity between black and yellow/black wires?)

Posted: Fri Sep 26, 2014 5:08 pm
Author: z1bman
max fuse should be 20 amp sounds like a coil has shorted internally. have you left the ignition on for more than five minutes or so ? have you got the points wires insulated with the fibre washers

Posted: Fri Sep 26, 2014 5:31 pm
Author: malmojoe
Thanks for your help both, I'll have a look tomorrow. Change the coils and check the points. None of which I fitted and both of which look a bit cheap and nasty. I'll have a look at the manual tonight too.

Posted: Fri Sep 26, 2014 8:46 pm
Author: ZedHead
Definitely sounds like a shorted coil