Took the bike out for a ride today. When I came to a stop I could smell sulphur. So I found somewhere to pull over and took the seat off. First though was that the battery is shagged. But it's a yuasa battery and less than 2 years old. Bike starts and runs fine and lights etc work all good.

The battery was very hot, but not leaking or on fire! So I rode back to a mates as wasn't near home, and got the voltmeter out. With the engine off after the short run I was getting 13.8v which seems ok from what Ive read. I started the bike up and revved up to 5000rpm and was getting 14.08v, which I think is still ok? I kept it revved and noticed the readings fluctuated quite a lot, going down to 6v and back up to 14v.
The R/R after idling for a few mins wasnt roasting - not sure if that's a good or bad sign?

I think the R/R is the original one,, and I suspect it's on it's way out. Any ideas on what the cause could be/other checks I can perform?

Update. Ended up riding home from my mates, when I got home, everything seemed ok, battery was luke warm, no smell of sulphur, voltage at standing was 13.5v. All good.

I'm not convinced though, and don't think it's fixed itself, still think the R/R is playing up...

I'd be very careful with this one mate - get the charging system fully checked and be sure that you won;t have a boiling or burning bollocks issue in the future!!

Couldn't agree with you more mate, NC30's don't go to well on fire, neither do I for that matter!

Just downloaded that charging system guide Rick O made, going to get amongst it tomorrow and see what I find.

On this note, does the frame usually get very hot? I note my frame get very very hot (transferred heat from the rr I imagine as is hotter closest to this) after riding for 45-60 minutes (though it is summer)

your RR is stuffed

i would also change the battery , its 2 years old anyway and after overcharging like that they arent good , prob find the plates inside are warped from overheating

Yup,rr is knackered by the sounds!

Had a quick look today, and pulled the R/R connector off...



Oh dear. But at least a lead. Unfortunately the bike has gone away for the day to have something fabricated. Will get it back tomorrow and continue to investigate.

Not much to investigate there.... it is fucked.

get a new connector, or fit spades to the loose wires and be sure that you get a nice soldered and crimped joint.

You'll want to check the other block in the right hand of the V - it also can get scabby and burned...and if that one is knackered..I would be looking under the genny cover to see how that looks.

@Icemaestro - yes - these bikes get bloody hot!

Thanks chaps, i'll be getting the replacement bits in as required.

You're not wrong there Mark, will take a dig at the alternator connector. If it's shagged I'll have to get at the stator coils, if I take the alternator cover off, would I definitely need to replace the gasket? Haynes says yes, inclined not to argue with it, but seeing what peoples experience of it is.

@johnnie5 new battery is on the list. Not worth chancing it, boiling bollocks is bad news !