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Fried coil
Posted: Mon Jun 05, 2023 5:23 pm
Author: z1bnackerkwacker
Hi folks,
Z1b.
Whilst going through electrics getting lights e.t.c to work, bike has been long term standing and not knowing anything of previous history.
I’d left ignition on and only got alerted by a crackle which fried right hand dyna coil. Boiling hot. Left was cold.
Checked spark at plugs and only on left coil was sparking.
Bit later nothing so checked points and spark and that had then disappeared
Someone had fitted new plugs dyna coils and Taylor leads prior to me getting it noticed when I pulled leads off that there are no nipples on plug tops.
Electrics not being my strongest point, anyone point me in the most likely cause, to start, do have multimeter, before I head out with fresh brain.
Don’t want to risk another coil till I have a better idea of cause.
Not in a hurry have inspection soon.
Not even started bike as yet
Re: Fried coil
Posted: Tue Jun 06, 2023 8:25 pm
Author: z1bman
If the ignition is left on for long periods it will burn out the coils
Re: Fried coil
Posted: Wed Jun 07, 2023 1:48 pm
Author: z1bnackerkwacker
Wasn’t long but thanks.
Waiting for bits now, dhl “parcel still in Manchester”.

Re: Fried coil
Posted: Wed Jun 07, 2023 7:15 pm
Author: gray
Does it have the " Wired George" mod feeding power to the coils ? That mod fried 2 dyna coils for me. You'll see a small modern-looking black box and some extra wiring under the L side panel or under the tank, with wiring feeding to the coils.
Re: Fried coil
Posted: Wed Jun 07, 2023 7:24 pm
Author: zapo
z1bnackerkwacker wrote:Wasn’t long but thanks.
Waiting for bits now, dhl “parcel still in Manchester”.

Out of interest how long was it?
Re: Fried coil
Posted: Wed Jun 07, 2023 11:36 pm
Author: z1bnackerkwacker
Less than a minute.
Got new coils, ignition and rectifier coming so should cover it.
Being f@cked about by dhl at moment tho’.
Re: Fried coil
Posted: Wed Jun 07, 2023 11:41 pm
Author: z1bnackerkwacker
gray wrote:Does it have the " Wired George" mod feeding power to the coils ? That mod fried 2 dyna coils for me. You'll see a small modern-looking black box and some extra wiring under the L side panel or under the tank, with wiring feeding to the coils.
Not noticed any odd boxes, don’t believe it has.
Re: Fried coil
Posted: Thu Jun 08, 2023 6:14 am
Author: relisysxx
z1bnackerkwacker wrote:Less than a minute.
Got new coils, ignition and rectifier coming so should cover it.
Being f@cked about by dhl at moment tho’.
It's almost like they know, if it's urgent they take forever but if you don't need it straight away it will be there next day!
Re: Fried coil
Posted: Thu Jun 08, 2023 11:34 am
Author: z1bman
gray wrote:Does it have the " Wired George" mod feeding power to the coils ? That mod fried 2 dyna coils for me. You'll see a small modern-looking black box and some extra wiring under the L side panel or under the tank, with wiring feeding to the coils.
It wouldn't have had anything to do with the wired george mod you must have had an over charging voltage
Re: Fried coil
Posted: Thu Jun 08, 2023 7:06 pm
Author: KeithZ1R
^^^^^^^^^^This ^^^^^^^^^^^^
Re: Fried coil
Posted: Sat Jun 10, 2023 10:02 pm
Author: z1bnackerkwacker
z1bman wrote:gray wrote:Does it have the " Wired George" mod feeding power to the coils ? That mod fried 2 dyna coils for me. You'll see a small modern-looking black box and some extra wiring under the L side panel or under the tank, with wiring feeding to the coils.
It wouldn't have had anything to do with the wired george mod you must have had an over charging voltage
Not had it running then, found the issue couldn’t see the coil live arcing on back of frame, so changed coil, new all in rect’ and dyna s, up and running now.
Annoying thing is I’ve tested coils off now and both read 0 ohms
Seems to be a bit rich but I’ll wait till I get a v5/reg number and take it for a blast first before fiddling further.
Examiner was here Wednesday, was happy says up to 4 weeks now.
Re: Fried coil
Posted: Sat Jun 10, 2023 10:15 pm
Author: z1bnackerkwacker
z1bnackerkwacker wrote:z1bman wrote:gray wrote:Does it have the " Wired George" mod feeding power to the coils ? That mod fried 2 dyna coils for me. You'll see a small modern-looking black box and some extra wiring under the L side panel or under the tank, with wiring feeding to the coils.
It wouldn't have had anything to do with the wired george mod you must have had an over charging voltage
Not had it running then, found the issue couldn’t see the coil live arcing on back of frame, so changed coils, new and all in rect’ and dyna s, up and running now.
There is actually a small grey rectangular plastic electrical item bolted to the underside of the left coil looks like original Jap’, “ Kyoto” two wires plugs into harness, wasn’t on my last Z1.
Annoying thing is I’ve tested Taylor coils off now and both read 0 ohms
Seems to be a bit rich but I’ll wait till I get a v5/reg number and take it for a blast first before fiddling further.
Examiner was here Wednesday, was happy says up to 4 weeks now.
Re: Fried coil
Posted: Sat Jun 10, 2023 10:43 pm
Author: z1bman
If its got a grey colored rubber its probably the stop light failure switch
Re: Fried coil
Posted: Sun Jun 11, 2023 7:19 am
Author: r3sc
z1bman is correct and it should be the brake light failure module but just double check as that unit should have a small rectangular connector block with 3 wires in it, not 2.
Hope it all goes well!
Re: Fried coil
Posted: Sun Jun 11, 2023 8:56 am
Author: z1bnackerkwacker
z1bman wrote:If its got a grey colored rubber its probably the stop light failure switch
Sounds like it.
Will answer below.