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NC23(K) Electrical Mystery - Long Post

Posted: Thu Jul 30, 2020 2:46 pm
by Astandane
Hi everyone,

I've recently been experiencing an electrical issue that so far I haven't been able to identify. This might be a bit of a long post as I want to give the best background I can, but I'll try and keep it concise.

The overall problem is that the bike randomly loses the whole electrical system, but it's not something I can reproduce, or attribute any particular circumstances to. It just happens. Here are all of the scenarios where it has happened:

1) On a mountain road on a hot day, stuck behind a lorry. Engine temp was rising but not into the red. Eventually find some space to get moving, and out of nowhere everything cuts out.

Manage to roll into a layby. Starter button produces nothing whatsoever. Turn bike off thinking I'm stranded. Come back a few minutes later in hope, everything magically works again. No issue for rest of the day, other start-ups are strong and normal.

2) On an open road, good speed, normal temps. Catching up to a friend who had pulled over. I stop so we can discuss where to go next (engine off). He sets off, I go to start, and nothing. Same as no.1 I wait for a while, everything suddenly comes back. Nothing else for rest of the day.

3) Going along a highspeed country road, finish an overtake and settle down to a cruising speed. Electrical system suddenly goes haywire, dials are all over the place, engine is sputtering. After a few moment everything recovers and I carry on, no more issues.

4) Last night, I get home from a friends in the city. Short trip at night. Pull up to garage door, slowing down to mount the curb as it's underground, bike cuts out. The difference here, is that as I press the starter, I'm getting an odd crackling sound from the lower right side of me. Starter isn't turning.

Get it into the garage and leave it for a while. Eventually the starter begins to turn, but is acting like it's working with a weak battery. Stick it on charge and go home.

After the 3rd occasion, I had decided it was time to go through as many of the electrical connectors I could, cleaning out with contact cleaner. Battery is new this year and has a trickle charger. Cables are connected firmly to the terminals. Bike has never blown a fuse.

I found that the 3-way connector from the alternator to the loom had begun to burn and melt inside - not sure on the cause.

As I live in Bulgaria, it was hard to actually find a replacement part, or the parts to build a replacement connector. I intend to do this, but as a stop gap measure, I removed the old connector halves, stripped the wires back a bit, and soldered them together and insulated. I know not an ideal fix, but I intend to do properly when I can.

Now, I haven't yet been able to check the charging current as I am waiting for a friend to lend me a multimeter, so I'll update that when I can.

But, given that last night was similar to the previous times, I am unsure if this is just relating to a battery charging fault, especially as it has always previously recovered normally.

To me this seems like a failing electrical component somewhere else, bad earth, or maybe some kind of short. I've not done much with electrics though, so I'm prepared to be wrong here.

Any thoughts are appreciated at this point. Thanks!

Re: NC23(K) Electrical Mystery - Long Post

Posted: Thu Jul 30, 2020 11:09 pm
by magg
You did not mention the chassis ground connection for the wiring loom or the battery -ve cable to chassis connection, have you checked them.

Re: NC23(K) Electrical Mystery - Long Post

Posted: Fri Jul 31, 2020 9:11 am
by Astandane
Hey, I checked the one that's next to the reg/rec and that appeared visually fine. Cleaned up the contact surfaces anyway. I'll have to try and check the rest over the weekend.

Re: NC23(K) Electrical Mystery - Long Post

Posted: Fri Jul 31, 2020 10:23 am
by magg
You could also check the connection of the main fuse located in the starter solenoid and the connections to the starter solenoid.

Re: NC23(K) Electrical Mystery - Long Post

Posted: Fri Jul 31, 2020 10:31 am
by Astandane
Thanks, will do!

Re: NC23(K) Electrical Mystery - Long Post

Posted: Fri Jul 31, 2020 4:23 pm
by CB1pod70
I think as Magg said it is probably the red (probably pink by now) connector on the starter solenoid which is situated on the lower right side where your crackling noise came from. There are 2 tabs which hold it in place and over time these snap allowing the connector to vibrate and then the connections go. You can get replacement connectors cheaply off ebay as they were used on loads of Hondas https://www.ebay.co.uk/itm/SOLENOID-STA ... SwGrBeU---

Re: NC23(K) Electrical Mystery - Long Post

Posted: Fri Jul 31, 2020 6:56 pm
by Astandane
Is this connector part of the ignition circuit once the engine is running? I'd imagine it's only engaged during start up, unless there's some kind of short which is tripping the electrics after that point.

Re: NC23(K) Electrical Mystery - Long Post

Posted: Sat Aug 01, 2020 12:54 am
by magg
The starter relay unit contains the 30Amp main electrical fuse. All battery power to the bike's electrical system passes through the associated connectors.

Re: NC23(K) Electrical Mystery - Long Post

Posted: Sat Aug 01, 2020 7:54 am
by Astandane
Alright, that makes sense then. I'll see what is going on there.

Re: NC23(K) Electrical Mystery - Long Post

Posted: Sat Aug 01, 2020 9:49 am
by Astandane
Update:

I was able to check the battery voltages today, readings are below. From my understanding, these values are fine.

13.2 with ignition off, charging for 2 days
12.3 with key on
11.2 with ignition crank
14.2 idle and with revs

Based on what I found when disassembling the start relay unit, I think it's more likely the fault was coming from there. Not the worst I've seen in terms of gunk and corrosion, but was definitely in need of a clean up. The bike fired up almost instantly afterwards.

I'll try and get some miles in and update the thread again over the next few weekends.

Thanks all for the help so far :plus: