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Offline MIKE550/4

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what would cause this
« on: January 13, 2014, 01:46:03 PM »
bit of background, bike has not been started in 30 years

Bike was stripped a few years ago and has since had powdercoated frame

on refitting the loom I found this bare patch




splitting the loom I found a green wire ( burned or rubbed not sure ) all I did with bike electrics was hook up the battery and test lights.

I am currently reading about wiring on the bike and been told earth wire fault or rubbing.

Now at rebuild stage of the bike and want to go through the electrics soon .

Total newbie to electrics so please talk in easy language

another pic after I split loom to look further 3-4 inches I think melted



so question is what would have caused this, the section is just before the connections which sit on plastic inner rear fender
« Last Edit: January 13, 2014, 01:55:31 PM by MIKE550/4 »
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Offline flybox1

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Re: what would cause this
« Reply #1 on: January 13, 2014, 01:52:32 PM »
it looks as though it was rubbed away....
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Offline MIKE550/4

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Re: what would cause this
« Reply #2 on: January 13, 2014, 01:56:09 PM »
edited to show 2nd pic
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Offline flybox1

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Re: what would cause this
« Reply #3 on: January 13, 2014, 02:07:39 PM »
wonder if it continually grounded itself against the frame, melting the casing back....
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'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline KrautKoffin

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Re: what would cause this
« Reply #4 on: January 13, 2014, 03:32:00 PM »
Looks melted to me. Recheck the grounds and clean up anything that even slightly looks out of the ordinary.
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Offline Stev-o

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Re: what would cause this
« Reply #5 on: January 13, 2014, 05:34:14 PM »
+1 melted.  Green = ground, that is puzzling.  How's the test of the harness?
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Offline tlbranth

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Re: what would cause this
« Reply #6 on: January 13, 2014, 08:24:27 PM »
I'm with Flybox. I think it rubbed through and subsequently became a partial, albeit spotty, ground. The heat generated by the bad connection did the rest. If it was purely a meltthrough, I don't think the damage would be so localized. So if you wrap the bare wire or splice in a new piece, rewrap the bundle and make sure your grounds are good, I'd say you'd be good to go.
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Offline bjbuchanan

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Re: what would cause this
« Reply #7 on: January 13, 2014, 08:27:57 PM »
I'm with flybox and Tl, rub then burn. It is just too isolated with no other clues/damage
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Offline dave500

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Re: what would cause this
« Reply #8 on: January 14, 2014, 12:10:22 AM »
someones hooked a battery back to front in its past,the earth wire always does that when polarity is reversed.
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Offline trueblue

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Re: what would cause this
« Reply #9 on: January 14, 2014, 03:00:50 AM »
Quote from: dave500 on January 14, 2014, 12:10:22 AM
someones hooked a battery back to front in its past,the earth wire always does that when polarity is reversed.
+1 or there is a power wire rubbed through/pinched to the earth wire and caused a dead short ;D
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Offline Bomberman

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Re: what would cause this
« Reply #10 on: January 23, 2014, 05:03:35 AM »
hi

so a newbie question, what sort of wire would you replace this with, is there a certain amperage wire i would ask for ?
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Offline Bomberman

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Re: what would cause this
« Reply #11 on: January 23, 2014, 12:27:56 PM »
so am I right in thinking

http://www.autoelectricsupplies.co.uk/product/66/category/11

28/0.30, 2.0mm2, 17.5A - cable OD 3.3mm would be ok to replace the section of earth wire
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Offline trueblue

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Re: what would cause this
« Reply #12 on: January 24, 2014, 03:54:37 AM »
I can't remember if these bikes use 2mm2 or 2.5mm2 wire. I was thinking it was 2.5mm2
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1979 CB650Z
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Re: what would cause this
« Reply #13 on: January 24, 2014, 06:39:35 AM »
Just get some 14 or 16ga stranded and you will be fine. If it were mine I would open the entire harness and subs.
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