No electrical power, lights, nothing!

[Tim400GB]

Bit of a strange one for you lot.

My nc30 was running and I was getting it up to temp to make sure the fan kicked in.

Soon as the fan kicked in the neutral light flickered and the bike stalled.
Started her back up happened again.

Now there are no lights on, one very dead bike.

My ignition switch is a flick button, the two black wires (switch live for the bike and switch live for the fan) have been soldered together and is connected to the permenant live via the button.

After a long day of servicing other bikes and having the carbs off the nc30 due to sticky floats I had to walk away from this issue before doing something stupid with tiredness.

So my question is could the fan kicking in and my ignition flick button wiring be the cause or is it coincidental? Has someone had this kind of issue before?

I did check the battery across the terminals (13v). And the battery earth to the frame is ok too.

My next step is to check the flick button/wires are ok and the 30A fuse is ok.
Any ideas/pointers welcome!

On the plus side, the engine and hrc spec carbs work woohoo!

[Tim400GB]

Found the no power issue.

The 30A fuse had blown. Could the fan cause it to blow? Want to find the route cause

[willandrip]

Has the fan motor seized; if so it will draw too much current and blow fuse. Test it manually.
Are the wires from the temp sender/fan sender to the fan suitably insulated.

Sounds like the fan is drawing too much current or once the sender is switching it on ,current is shorting to earth.

[Tim400GB]

I did hear the fan kick and spin for a second.

Hopefully during the week I'll get the multimeter out to check the fan wiring. I find it odd that it would blow the main 30A fuse and not the 15A fan fuse.

Think I'll check the regulator rectifier to make sure it's not over charging.

[Neosophist]

overcharing might not blow any fuses, which are current based rather than voltage.

Hmm.

The fan should be easy to test, take the wire off the fan switch and ground it out with the bike switch one, the fan should spin.

you could have a loose wire / broken insulation somewhere that touched earth which could blow your mainfuse. bit of guesswork but youll find the issue

[Tim400GB]

Ok update.

Ignition on, engine off
Ground the fan switch to chassis - fan comes on, in the right direction.
All ok

Ignition on, engine running @ idle
Ground the fan switch to chassis - fan comes on, in the right direction.
All ok

Charging check V across battery
13v ign off
13.7 @ 5000rpm
13.9 @ 7000rpm
Good

Resistance check of the reg rec plug comes out as basically zero
Good

Now I'm pulling/bending at the loom to try and make a short.
Nope, still have power.

Sounds weird but I want to find a fault.

Only thing left to try is get the bike hot again and make sure it doesn't cut out when the fan kicks in again?!?

Maybe a duff fuse?

[Neosophist]

might have a lurking short somewhere thats hard to find, perhaps (and its a long shot) the heat made the wire more flexible and something shorted out somewhere..
if you cant find it just by movign the wires about then unless you have loads of time id try it out again and see what hapepns, just make sure you have a spare fuse in the spare fuse holder and if it happens again youll need to do some further investigation.

[Tim400GB]

My mind was thinking along the same lines. Bought a few 30A fuses, so at some point I will get the fairings off, get the bike hot again and start prodding/moving wires/harness etc to see if I can get it to blow.

I like the suck it and see approach too tho.

[Neosophist]

Had a couple of similar problems in the past, if its not shorting now and you cant seem to make it then its like looking for a needle in a haystack, can drive you mad and turn into a complete teardown.

do a couple of local runs incase it shors out and you cant get it running again but if you can get it to happen again maybe easier for you to find.

im sure youll get the problem in the end. Was it raining or been damp/ could have had some water somewhere.

my big scooters terrible in the rain always misfiring, gotta find where the watres going

[Tim400GB]

Nope. No water present. The bike is a fresh build.

I did give all the plugs a good dose of ac90 which I noticed an excess of when running the bike.
Maybe it was that causing the short