Honda regulator problem?

I have an 85 Honda CBX750 which helpfully has a voltmeter. Yesterday though
the voltage reading dropped steadily down (to 8 volts) and I only just made
it home. Inspected the battery and found a wire burnt out - looks like it
had been worn down and burnt out when too much current passed through? The
rest of the loom was OK and resoldered it back together good. Started the
bike (with jumpers as the battery was nearly flat) and the voltage got to
about 11.8 and just made it above 12 when reving high.

This doesnt look too good so I put the battery on a charger for an hour and
it has accepted the charge fine. Plug the battery back in and the bike
starts but the voltage still sits on 12 and drops to 8 or 9 with headlights
on. The regulator (which is large unit with cooling fins) gets hot so I
presume the alternator is OK. I guess that means the regulator is toast but
electrics are a bit of a mystery to me, what should I try next?

 

In aus.motorcycles on Sun, 16 May 2004 10:53:43 +1000

Go to http://aigor.org select the Tech Tips, and from there Electricals.

There are several links to useful troubleshooting pages, the Electrex
one is particularly good. (select tech support when you get to the
Electrex site)

Zebee

 

http://www.teamrc17.net might be able to help.

Nev..
'03 ZX12R

 

Ok,

Well I checked out the links that you both gave me and have printed up a lot
of material to read. Thanks for the pointers! Tonight I managed to do some
more testing following the fault finding diagram from the electrolux
website. One of the steps asked to put the red multimeter lead on the
battery negative and the black multimeter lead in the negative output of the
regulator. I did this and the reading was .026 volts. This apparently means
that there is a bad connection from the negative lead on the regulator to
the battery negative. So I ran a new lead direct but still got the same
reading so I just proceeded to the next step?

The next step involved finding an extra wire from the ignition switch and I
couldn't do that without the wiring diagram so went to the next step which
was to test the output directly from the alternator (stator?). All three
wires measure 1 ohm which is fine apparently but when the engine is above
5000rpm it should output at least 50volts AC, it did not. All three gave
readings between 9 and 11 volts AC.

The guide says this means the stator is at fault - is this consistent with
my story so far? How should I go about replacing this? Is it the entire
alternator unit? If it is where should I get one in Brisbane or should I
just write this off as too tricky for someone of my limited talents and pay
someone?

Thanks for any advice!

 

stator reading low, needs replacing

usually regulators when they decide to pack up and die put out high volts

 

Please excuse my ignorance but is the stator *inside* the alternator or is
it *the* alternator? I see references to both in my travels so far. Any
pointers for where to get this in Brisbane and approx what is a fair price
for one?

Cheers!

 

It's one half of the alternator, the other being the rotor. One holds still,
the other spins around.

If your bike is like most, pulling off the left-hand engine cover takes the
stator, which looks like some species of alien sunflower, with it and
reveals a vaguely bowl-shaped object bolted to the end of the crank. That's
the rotor. It spins around and induces an AC current in the "petals" of the
stator.

 

Had an apparent Reg/rectifier issue very much like what you describe.
turned out to be the battery not the reg. I suggest borrowing someones
battery for a while and see if you get the same result with your
battery in someone else (preferably a honda as they all have wierd
reg/rectifiers).

 

Thanks for the help. Looks like its the stator (and i removed the cover and
had a look). Turns out it was the positive output wire of the regulator that
shorted and disconnected which is not very good for the alternator. Every
test on the fault finding guide for the alternator failed and I am testing
the regulator tonight before I order any replacements.

Thanks!

 

Yep - and if you're really unlucky, they burn too. Burn REALLY hot. Hot
enough to start aluminium fires, as I discovered one night at 10,000' over
the Northern Territory.....exciting stuff When that big red 'over volt'
light goes on and the ammeter get's pegged at +20A going into the battery
life gets interesting to say the least.

The other time a volt-reg in an aircraft died on me, it boiled the battery
to the point there was just a molten blob of goop in the box designed to
contain just such an event. That was weird though; I shut down the
electrical system, pulled the alternator circuit breaker and did all the
'no electrics' flying frufru (like pumping the wheels out by hand....with
no autopilot......in cloud - fun). Apparently something burned out in the
wiring loom before I'd pulled the plug and the alternator kept feeding big
volts to the battery. Nasty.

James
ZZR250==>ZX9R

 

The alternator has two parts: the rotor which rotates, and the stator
which doesn't. On many bikes[*] the rotor is a set of magnets on
the flywheel on the end of the crank, and the stator is a set of
coils attached to the sidecover so they project 'inside' the
cylindrical rotor.

You may be able to get a replacement stator from a wreckers,
failing that the coils can be rewound by a specialist. Small
Coil Rewinds in Geelong has a good reputation.

-----sharks

[*] Usual Spagthorpe disclaimer. Blah blah cold fusion Blue Heeler.

 

What colour's the wire, and where does it go from/to? Is the
break somewhere where it could have rubbed against the chassis
or whatever?

-----sharks

 

I traced the wire last night and it is the positive output from the
regulator. It could well have shorted to ground when it blew. I am doing
some last tests tonight on the alternator and RR but it looks like the
stator for sure. Found a wrecker in Brisbane who will do one for $165
exchange. No other wrecker in Brisbane had one so I guess thats mine

 

Ah, right, yeah that could burn a stator out if the reg didn't go
first ...

Not bad value, considering what a rewind would set you back. I was
delighted to get hold of a set of XLV coils for $200 ... none of
the teamrc17.net folks had a stator to sell you?

-----sharks

 

hopefully this is between wires? voltage check should be between wires with
the stator disconnected from regulator!!!
yes, you should have 50-100 V AC at anything above 2000 RPM...if you have 3
yellow (or white) wires, red & black at regulator and stator is low on
voltage...stator is problem

check from wires to ground also with engine off...should be infinite
resistance, ie stator is not earthed


however...some honda's have a field coil alternator (CB750/900/1100 for
one)...distinguished by 7 wires at reg 3 yellow, stator coils; red&black;
power&earth, AND 2 others that control the field
instead of using a fixed magnet rotor, these alternators have magnetic field
adjusted by regulator...another thing to go wrong as they have brushes
inside
so bear this in mind and have a look
if its one of these systems the brushes are suspect as is rotor coil...from
memory rotor coil is 5 ohm or so, check resistance with reg disconnected and
also check if brushes are worn too much
if you supply 12 V to the field circuit you should get full power...the way
to check this is by disconnecting regulator, then connecting field coil to
battery
if you get 50-100 V AC, regulator is kaktus, if not rotor or brushes or
stator are...sort through one by one

 

hi blenny

i replied to this 2 days ago, but me f ing
usenet server shit itself.

but, very briefly, i'll go over some
of the comments...

yep.. that sounds about right. (i used to have a CBR600 93'
a few years ago).

unless you have a "true RMS" voltmeter (and
a cheap one is a few hundred), your AC
measurements will be wrong.

9-11 volts sounds about right from a crappy
$25 digital multimeter.

if you have a oscilliscope handy, then
you measure the peak voltage (between
the phases) and multiply it by 0.57735.
that will give you an RMS voltage value
for 3 phase output.

just for your reference, i measured by
ex-CBR600's alternator a few years ago
and got 40V RMS (no load).

sounds like you are checking earth coupling of the
regulator. 0.026v sounds good enough. you could
try reseating the earth couple, but i bet you
have cheap a multimeter and there is probe lead
resistance and measurement error because it's
cheapy.

itz ya multimeter. shit silcon.

my guess is that your regulator has
"gone to god". unbolt it from frame.
unplug it. take a close look at it.

did you have a job unplugging it ?
(maybe the connector leads have melted
into the pins.. due to exceed heat
caused by short out in regulator)

does it look discoloured ? is there a
hole in it ?. does it look burnt ?

with the head light connected, how
long does it take to get hot ?.

30 seconds ?. 2 seconds ?. 2 seconds
with light load would definately suggest
an internal short out.

does your multimeter have diode tester ?
regulators can be tested this way too.

give me a picture of your regulator
pinouts (just a text piccy). i bet
it's identical to my old blades.

maybe, but there is some basic fault finding
you can do that will save you some $$$.
electrics is very misunderstood thing, even with
mechanics who will root around, get no where
and charge you for their learning curve.

-f

 

Ok,

Thanks for all the help. I replaced the stator and all is well now. And I
actually know something about the charging system on my bike.

Thanks again for the replies, it has saved me paying an auto-electrician!