Author Topic: cb500 dead short  (Read 2653 times)

Offline RGP750

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Re: cb500 dead short
« Reply #30 on: May 12, 2023, 07:10:30 PM »
Up date.
Well I took everything off I could find including the battery.
Did the continuity green?black test on the loom and couldn't find anything. Put loom back on and
fuse NOT BLOWING ,put together rear light wiring , tested , Ok switches OK horn ok everything else all ok .
A eureka moment fuse still ok . Now here is the next problem , what the hell is wrong now. Nothing works :-\
no horn, starter, dash lights rear light Nothing. What the hell have I missed.  HELLLLP!!!!!
Done Battery test and 12v
1972 500/4
1973 CB175
1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

Offline SteveW

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Re: cb500 dead short
« Reply #31 on: May 12, 2023, 07:15:37 PM »
Are your fuses okay? I had a problem on my 550 where everything died, turned out the fuse looked intact but had just degraded with age and was open circuit.
1974 CB550 K0
1980 CB650
2000 CBR929RR Fireblade
1966 Lambretta LI150 Series 3
1981 RD350LC
1972 Raleigh Chopper
1974 Raleigh Tomahawk
2011 Henry Hoover

Offline RGP750

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Re: cb500 dead short
« Reply #32 on: May 12, 2023, 07:18:33 PM »
Hi Steve
Please see the start of the thread cheers
1972 500/4
1973 CB175
1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

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Re: cb500 dead short
« Reply #33 on: May 12, 2023, 07:49:58 PM »
Can you measure volts coming out of the fuse now, en route into the loom ?

Offline RGP750

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Re: cb500 dead short
« Reply #34 on: May 12, 2023, 08:16:48 PM »
what meter between fuse and red wire going to ignition switch?
1972 500/4
1973 CB175
1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

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Re: cb500 dead short
« Reply #35 on: May 12, 2023, 08:31:24 PM »
Yes, to check if anything is now going into loom.

Positive lead to fuse exit, negative lead to battery -


Offline RGP750

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Re: cb500 dead short
« Reply #36 on: May 12, 2023, 08:38:31 PM »
OK Back track.
Just found out why nothing working, knew it would be something stupid OOPs! multi plug on the loom not plugged in :-[
But now I have plugged it in Fuse has blown so where to look now.
1972 500/4
1973 CB175
1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

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Re: cb500 dead short
« Reply #37 on: May 12, 2023, 10:08:16 PM »
Looking more like it'll need unwrapping to understand it.

If there's nothing obvious, and it still blows the fuse when nothing is connected (any devices) to influence the outcome, then it must have some compromise inside.

Offline RGP750

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Re: cb500 dead short
« Reply #38 on: May 12, 2023, 10:21:29 PM »
if it didn't blow before I connected the multiple in the side panel would that not mean the problem in in whatever the socket is connected to ?
1972 500/4
1973 CB175
1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

Offline Bryanj

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Re: cb500 dead short
« Reply #39 on: May 13, 2023, 07:50:55 AM »
That suggests the main loom is a problem as the fuse is not connected till that big block is connected due to being part of the sub loom.

Offline RGP750

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Re: cb500 dead short
« Reply #40 on: May 13, 2023, 08:11:13 AM »
Thanks Brian just done this this morning.
Disconnect block, check black live into headlight for continuity and all is fine , plug block in and it shorts.
I then check black in sub loom and ok, check black on regulator ok. Something is happening when it is plugged in .????¿
1972 500/4
1973 CB175
1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

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Re: cb500 dead short
« Reply #41 on: May 13, 2023, 10:00:24 AM »

Have you tried it with just the rectifier plug disconnect & the flasher unit not connected?
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Offline RGP750

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Re: cb500 dead short
« Reply #42 on: May 13, 2023, 04:40:51 PM »
Don't want to rejoice just yet but it looks like the whole mess is down to a faulty Indicator relay.
I have ordered a new one and will report back.
Looks like Ted may get first prize.
Watch this space
Cheers all for your thoughts.
1972 500/4
1973 CB175
1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

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Re: cb500 dead short
« Reply #43 on: May 13, 2023, 07:16:08 PM »
The flasher unit on my old 400 was this inside after standing for over 10 years.



.flasher unit by Macabe Thiele, on Flickr



Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Offline RGP750

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Re: cb500 dead short
« Reply #44 on: May 13, 2023, 07:41:30 PM »
think that's shot. mine was a repro only fitted 2 years ago. >:(
1972 500/4
1973 CB175
1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

 

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