Been having some issues with my NC30, was out one night and the battery died, checked the reg/rec plug and it was melted, so cut off the plug and used crimp terminals and fitted a new Honda reg/rec, checked the charge rate and all seems ok without the lights on, however, the other day I had a flat battery, now I can only put this down to running with the lights on so the battery wasn't getting enough charge. I've since replaced the battery as it was of an unknown age and branded Aero, so I've fitted a brand new Varta.

Basically without the lights on at 5000RPM the charge rate getting to the battery is ok but with the lights on it drops to 12.6v, is that too low? what sort of figures would you expect?

Output at the rectifier live & earth is 14v but I've not checked the output of the alternator, I'm also wondering if I should consider wiring the rectifier direct to the battery??

Any thoughts?

pockets wrote:Been having some issues with my NC30, was out one night and the battery died, checked the reg/rec plug and it was melted, so cut off the plug and used crimp terminals and fitted a new Honda reg/rec, checked the charge rate and all seems ok without the lights on, however, the other day I had a flat battery, now I can only put this down to running with the lights on so the battery wasn't getting enough charge. I've since replaced the battery as it was of an unknown age and branded Aero, so I've fitted a brand new Varta.

Basically without the lights on at 5000RPM the charge rate getting to the battery is ok but with the lights on it drops to 12.6v, is that too low? what sort of figures would you expect?

Output at the rectifier live & earth is 14v but I've not checked the output of the alternator, I'm also wondering if I should consider wiring the rectifier direct to the battery??

Any thoughts?

Yes that is too low. Ideally it should stay around 14v.

First off do not crimp the connectors, they need to be soldered. They carry high amps and any corrosion etc will cause them to melt (like the old plug).

I have to goto work now but im sure somebody will be along with relevant testing info.

You should get at least 14 volts with lights ON at 5000 rpm. Have you measured the resistance between the three yellow wires from the stator at the rect/reg plug?

Thanks chaps.

magg wrote:You should get at least 14 volts with lights ON at 5000 rpm. Have you measured the resistance between the three yellow wires from the stator at the rect/reg plug?

Not yet, I ran out of time yesterday and I can't get to the bike until mid-week. Does it have to be measured at the reg/rec end or can I measure it at the plug by my right knee? will also get a multimeter that measures AC as mine only does DC so I can measure the output of the stator.

Best measured at rect/reg, with rect/reg unplugged, because the results will indicate if the complete circuit between the stator and rect/reg plug is ok. Unusual to find a multimeter that does not measure AC and DC.

magg wrote:Best measured at rect/reg, with rect/reg unplugged, because the results will indicate if the complete circuit between the stator and rect/reg plug is ok.

That doesn't make sense. If he measures the reg/rec he won't get any reading from the 3 phases.

You need to unplug the reg/rec and test the stator lead (the lead with 3 yellow wires that disappears into the engine casing). Set the multimeter to ohms and short the test leads, this will give you the meter's internal resistance. Note this figure. Then test across each phase in turn, it doesn't matter which way round the test leads are.

So you need to test thus:

Phase 1 ~ Phase 2
Phase 1 ~ Phase 3
Phase 2 ~ Phase 3

Note each resistance value and subtract the meter's internal resistance. Post your results up here.

The resistance from the rect/reg plug yellow wires, with the rect/reg unplugged, down to the stator and back to the rect/reg plug will tell you how good the connections are in each path and indicate the stator coil resistance.

Which part does not make sense?

Ah I see now what you meant. It was just the way I read your original post, it came across as though you were suggesting he tested the reg/rec connections.

In an earlier reply to pockets I had identified the wires, the latter post was a clarification and inquiry as to the measurement results.

Did you sort this pockets? My brother has very similar issues!