Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: davidrsmith on July 24, 2019, 07:41:46 PM
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Hi,
I rode my K3 to work today, about 2 miles from home I had to do a left turn, as I did the turn all of the electrics died and the engine cut out.
I checked the fuses, a 15amp one was blown so I put spare in, turned the ignition on and nothing.
I ended up pushing the bike home as I couldn't get anyone to pick it up.
When I had K3 years ago a local shop did some work and routed the cables to the bottom of the ignition cables incorrectly so when going around a bend the contacts broke and the ignition cut out, remembering this I tried waggling the ignition wires but not a flicker.
Someone tried to jump start the bike but again absolutely no electrics.
Anyone got any ideas please before I start looking at it during the weekend
Thanks Dave
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First suspect would be ignition barrel contacts if supply is definitely going out via main fuse.
See if volts arrive at back of ignition switch, then if they come out again.
Break it down into sections until you lose the supply, battery to fuse, fuse to ignition switch, switch to loom etc
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As a quick reality check, take a supply from battery positive to coil supply plugs under fuel tank (not the wires that go to the points as they are earth)
Then kickstart it, should run like that ( just the engine but no lights) but will verify you've lost the switched supply somewhere in the loom.
Just got to then find it ;D
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Ignition switch gave issues on my k3. Other places to look are all the red and red with white tracer wires in the contacts under the covers by the battery, these tend to grow green fur and fall appart, excluding that I found these old Hondas to be pretty reliable electrically speaking.
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If you need a volt meter https://www.dx.com/p/uni-t-ut120c-portable-1-8-lcd-digital-multimeter-grey-red-1-x-cr2032-2018228?tc=GBP&ta=GB&gclid=EAIaIQobChMIxduE0LLO4wIVw-FRCh3mYwx8EAQYBiABEgLXKvD_BwE#.XTjBEN5wbMI are really good for this sort of thing.
Low cost, small enough to carry around with you, excellent little meter for all "hunt the volts" tasks ;D
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Talking of multimeters this arrived today as I needed a DC clamp meter to do a job. A nice little meter with plenty of functions and readings are comparable with my Fluke. https://www.ebay.co.uk/itm/True-RMS-Digital-Clamp-Meter-Multimeter-AC-DC-Voltage-Current-Capacitance-Q5B3/233287651400?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649&redirect=mobile
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these tend to grow green fur and fall appart, .
Like my battery cable Matthew
[attachimg=1]
[attachimg=2]
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these tend to grow green fur and fall appart, .
Like my battery cable Matthew
(Attachment Link)
(Attachment Link)
I hope you used a big block connector to mend that. ;D
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these tend to grow green fur and fall appart, .
Like my battery cable Matthew
(Attachment Link)
(Attachment Link)
I hope you used a big block connector to mend that. ;D
I was tempted Chris but it kept crumbling further and the ends wouldn't reach the block connector any more 😭😭😭 I jest, Trig made me buy a new one 😊
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As the person who keeps every removed part, just in case theres some chance of saving it, I must shamefully admit I have binned wires in that condition as beyond saving!
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Desirable attribute in antiques, they just call it verdigris ;D
They like a bit of patina that lot.
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I also had problems with ignition switch, everything cut out including lights, very scary.
I now have an ignition switch from an Austin A35 car.
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I also had problems with ignition switch, everything cut out including lights, very scary.
I now have an ignition switch from an Austin A35 car.
Did you get a free bottle of smoke with it. :D
[attachimg=1]
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Another vote for ignition switch. Same happened in my K3. Put a DSS one on whilst the original one is being sorted.
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I also had problems with ignition switch, everything cut out including lights, very scary.
I now have an ignition switch from an Austin A35 car.
Did you get a free bottle of smoke with it. :D
(Attachment Link)
:D Lucas wiring works by magic and alchemy and is fine as long as you keep believing in it. :D
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Do you mean St Joseph Lucas, prince of darkness with his intermittent electron?
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Hi
Thanks for the advice, I have charged the battery and checked the voltage at the main fuse, approx 13v at both ends of the fuse.
I have taken the electrical connector off of the ignition switch, I checked the voltage on the red wire and it is about 6.9v. I shorted the red wire to the black wire on the loom side of the ignition switch and still nothing, no indication lights, horn or electric start.
I have looked at the circuit diagram, there doesn't appear to be anything between the fuse and the ignition switch plug that should be causing the volts drop unless the red wire is shorting but I would expect that to have blown the fuse.
Anyone got any ideas?
Many thanks
Dave
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Further to my last post, I connected a wire from the red wire in wiring loom plug that connects to the fuse panel to the black wire that is on the plug that connects to the ignition switch, thereby missing out the main loom red wire from the fuse and the ignition switch.
The neutral light and the oil light came on.
I did have a fuse in my connecting wire.
So it looks like my red wire from the fuse to the ignition switch may be partially broken somewhere in the main loom.
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Missed your previous post :-[ but would have done as you've continued.
They are usually suspect at the peak bend point where the loom passes the frame head stock inside the large plastic sheathing. As you rotate the steering they can eventually compromise the individual wires inside.
You can, if you've got a sharp meter probe, check at different interval along the wire to pinpoint it's damaged part by pushing in through the individual wire insulation.
Either way it'll need a repair of replacement run from end to end.
At least you've essentially found the fault now so can plan a cure.
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The normal culprit,which you bypassed with your test, is the connection from the wires to the fuse holders that corrode also connection between fuse itself and the clip.
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Hi
Yes, Bryan I agree, so I have decided to take out the fuse panel and replace the wires from the fuse holder to the connector block, and also replace the wire from the electrical panel to the ignition switch plug.
I have just been to my local bike shop to try and get some spade connectors/sockets and a tool for inserting/extracting the connectors from the plugs, they couldn't help.
Can anyone advise the best place to buy such bits from?
Many thanks
Dave
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https://www.autoelectricsupplies.co.uk
http://www.vehicle-wiring-products.eu
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To get the connectors out of the plugs use jewlers screwdriver or dental pick
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Hi
I have now replaced the red wire from the fuse box to the ignition switch plug, I now have 12.8v at the ignition plug.
Still nothing when I turn the ignition on, I have done some continuity checks on the switch whilst turning it on and it is open circuit.
Can I change the connector block on the bottom of the ignition, thereby keeping the same key?
Does anyone have an old ignition switch for a K3 for sale?
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750F1 /F2, 550F1/ F2 and 400F1 and F2 will also fit, makes it easier to find!