NC24 Electrics as usual... Really desperate now!

[Utopic]

Hey guys I'm still having problems with my main fuse blowing. I've done the following tests and these are my findings:

Removed 3 yellow wires and all combo's tested 0V with the engine off (ac testing)
With engine idling all combo's tested around 20V

Reconnevted the wires, switched to dc and tested batt.
Engine off:12.47V
Idling lights off:13.3V
5000rpm lights off:12.9V
Idling lights on:11.77V
5000rpm lights on:12.8V

To be honest I don't know what this means but its the same test I was told to do a while ago. My batt doesn't seem to be getting any charge I don't think cos it keeps dying and I still don't know if its a faulty regulator that's causing this and my main fuse to blow. Please help I'm getting desperate here, I wanna start spending money on getting her to look nice now, not constantly reworking my electrics. Thanks in advance!!!

[Neosophist]

Hey guys I'm still having problems with my main fuse blowing. I've done the following tests and these are my findings:

Removed 3 yellow wires and all combo's tested 0V with the engine off (ac testing)
With engine idling all combo's tested around 20V

Reconnevted the wires, switched to dc and tested batt.
Engine off:12.47V
Idling lights off:13.3V
5000rpm lights off:12.9V
Idling lights on:11.77V
5000rpm lights on:12.8V

To be honest I don't know what this means but its the same test I was told to do a while ago. My batt doesn't seem to be getting any charge I don't think cos it keeps dying and I still don't know if its a faulty regulator that's causing this and my main fuse to blow. Please help I'm getting desperate here, I wanna start spending money on getting her to look nice now, not constantly reworking my electrics. Thanks in advance!!!

Then fix the problem properly.

The battery isn't getting charged.

The generator seems to be outputting power, what do you get at 5000rpm? It should be circa 50v AC.

When / how does it blow the main fuse? This should only happen with a bad short circuit (it will need to pull more than 30amps!) This shouldn't be very difficult to find.

Perhaps a freyed wire touching the frame occasionally.

[Utopic]

Thanks for coming to the rescue again Neo, I am trying to fix the problem properly. What should be at 50V at 5000rpm, the yellow wires?? It blows infrequently but most often literally 2 seconds after I start it up just as I'm about to pull off ie as I'm letting the clutch out. Would a short somewhere cause the battery to drain or might the short have killed the batt if there is one?? Got the whole weekend to try sort everything out. I've also attached a wire from the reg/rec's base plate to the subframe after the first 2 shorts, could that be a bad idea? I guy I know here who knows a bit about bikes suggested that but I was a little suspicious about that. I'll remove the wire again and try again and hope for the best.

[magg]

If the suggestion I made in your other post as a starting point to test for a short circuit it did not help try this.

New fuse, disconnect rect/reg plug, fully charge battery, start engine, ride around the local area with a pocket full of replacement fuses.

If all goes well then dud rect/reg is a possible source of your trouble and would also explain why your battery is not charging.

Beware it sounds like an intermittent fault so although it may appear initially to be fixed, it might unfortunately reappear.

Extra earth wires are not normally needed at the rect/reg, although heat transfer compound between the rect/reg base plate and the chassis is a good idea to help cool the rect/reg.

Yes Neosophist is referring to the three yellow wires when asking about the AC voltage at at 5000 rpm.

[Neosophist]

Yep, 50v AC on yellow wires at 5000rpm (remember to have them disconnect from the reg/rec)

Magg's suggestion seems pretty good, if anything it'll isolate the reg/rec.

Seems strange that it's intermittent though, since the reg/rec is solid state i'd assume once it's gone to the point of causing a short to blow the main fuse it wouldn't be intermittent.

Get all the panels off so you have access to the wiring loom, tank off and temporary fuel tank from a plastic bottle / pipe etc and start poking the wiring loom with a stick, make sure you move it about some.

Check your starter motor cable (big thick black cable to the start motor) isn't freyed and touching earth sometimes.

For it to blow the main fuse and not the accessories there has to be a short with something connected directly to the battery, this doesn't leave a lot so it shouldn't be too hard to find!

[Utopic]

Ok cool, I did the test with the stator wires and they were all around 50V at 5000RPM. I'm going to do exactly what you guys suggest. It makes sense that the short is in the starter circuit because like Neo said, none of my other components are blowing. Thanks a lot guys, today I'm almost certain that I'll find the short, I completely stripped her down when I did the initial tests so with a good eye and good fortune I'll be able to isolate the short. I insulated the -ve terminal as it had a few frayed wires and re insulated every spade connector that I've put on. Wish me luck!