Alternator stator

I had a flat battery on the silverwing on Saturday morning, it's a 2013 with 27,000 miles.
I charged the battery for a hour yesterday and the engine started straight away.
I checked the voltage and
On tickover it was 12.3 volts
At 5,000rpm it was 14.1 volts
but with main beam on it was 13.1 volts.

I disconnected the stator plug today and checked the resistance between the yellow wires
1 to 2, 1 to 3 and 2 to 3 were all dead shorts.
All three wires to earth are a dead short.
Does this sound like it is "definitely" a faulty stator ?
I don't want to buy a new one if this could be a different fault.
Thank you for any advice.

Electrical stuff is not my forte but, if you haven't already done so, type 'stator' into the search bar above. (Bad Stator parts 1,2 and 3).Our dearly missed cosmic_jumper (Tim) had some stator issues which make for interesting reading.

Hi David.
I would say from your first paragraph you are getting some form of charging due to the differences in voltage readings/RPM.
That said a common fault of the Swing is leaving the under seat light switch on when you shut the seat which will result in a flat battery the next day, I removed my bulb when it happened to my Swing.

With reference to Stator readings it takes a good multi-meter to read the difference between 0.1-0.5 of an Ohm and a dead short enclosed screen shot.


Hope this helps, shout if it keeps happening.

Be safe, be seen!

Find a known good multimeter first a lot of times the internal fuse can be blown from improper testing and Ohm readings just don't work. If everything was shorted, it wouldn't charge at all. It will read voltage but Ohms is fused on all the meters I know of.

Have the battery checked also internal short.

It seems very unlikely that you would see 14.1V with a dead alternator so I agree with others that that is unlikely to be a fault. You can also check the AC (NOT DC!) voltage at the disconnected alternator plug across each pair of yellow wires while running; should be at least 50V AC on each of the three phases @5000rpm.

In my experience batteries don't last as long as you might hope, and 3-5 years seems to be a common lifespan. They fail with internal shorts that result in reduced charge-holding ability and eventually become a deadweight in the charging system that sucks up power.

If I was diagnosing a charging fault I would spring for a new battery in the first instance just so you can rule that out as a cause.

Thanks for all your advice.
I checked the AC volts today and got 50 volts at around 4,000 rpm and it kept going up as the revs increased so it must be charging.
I also noticed a lower ohms setting on my multimeter, I was using the second setting not the lowest yesterday.
With this lower setting I was getting a reading of 0.5 when touching the probes together and when testing the yellow stator wires I had a reading of 0.7 so I'm assuming I was getting a resistance of 0.2 which is within the honda spec of 0.5 to 0.1.
So I'm going to get a new battery tomorrow and hope that'll solve the problem because I have no idea how old this one is, it could be the original 10 year old one.

One other thing to consider is the electrical resistance of the alternator plug; it is quite common on other Hondas (my VFR800 for instance) for the plug to get a bit wet and then the terminals start to corrode which increases their resistance and reduces the charging voltage. I'm sure this can apply to any critical connection in the charging system but the 3-wire plug seems to be the worst, so make sure that yours is clean and free of oxidation. In extreme cases the high resistance causes enough heat to melt the plug which can allow the three phases to connect. Bad Things happen then.

The voltages you stated seem close to normal and the alternator good.
I would remove the bulb under seat; it’s difficult to know if it is off when seat closed.
A healthy, well charged battery should give 12.6 - 12.8 V, after starting, charging voltage 14.1 -14.5 and lowers to 13 (ish) after a full charge.