Hello, John Talley here with partzilla.com. Today we're going to be taking a look at
the charging system on our 2012 Honda TRX-420. Now typically it's either down in the engine
in the stator and rotor, or it could be the voltage regulator and rectifier. And we're
going to dive in and I'm going to show you how to figure out which one could be bad on your
unit. So if you're ready, let me go grab a couple of tools, and we'll start picking this thing apart.
Now your charging system is basically made up of three different sub systems if you will. You've got
a stator and a rotor down inside of the engine, which is producing an AC signal. It sends the
AC signal up to the voltage regulator rectifier. Now its job is to take that AC voltage and then
convert it into a DC voltage, which is then used to charge the battery and run the systems on the unit.
So there's three things we need to check. One, we're going to start with the battery. We're
going to take a static and then a running voltage to see if it's charging. Now that point we need to
determine, well, is it the regulator rectifier or is there a problem with the stator and the rotor, and
I'm going to show you the technique we can use to determine which one's which. So let's get the seat
out of the way, get to the battery, take a couple of measurements, and then we'll work our way forward.
For those unfamiliar with the Honda TRXs they're really easy to get to well, your critical parts of
the machine without any tools. The seat you just simply reach behind and there's going to be a
little tab or actually an arm that you lift up, release it, and then it pulls away. Now to really
get access to where all the electronics are, we want to drop the rear tail section.
Now, lift up on the front edge of this cover. It's just held in by a couple of grommets, and slide it
forward, then it releases. The first thing we want to do is take a look at the battery, see what type
of voltages we have. We want to see somewhere north of 12.3, 12.4. That usually indicates a
pretty healthy battery. Let's see what we have. So we're going to bring it around to DC volts.
12.14, and that's a little on the low side, but it should be enough to start this. But what we're
really looking for is not so much the voltage now, but the voltage when it started in between 13.5
all the way up to 14, depending on what RPM the engine is actually running at. So let's flip her on.
All right.
That is actually under the 12 volts, so in a very short period of time,
it would run it for a while but it's going to end up killing this battery because it's
not being charged at all. So what we're going to do is go back to the regulator rectifier,
and we're going to pull the connection that runs up to the stator and the rotor and we're
going to take an AC measurement to see if it's outputting anything. So we just want to push in on
this button at the top-- or this lever at the top rather-- then use our screwdriver to gently pry up
and then she disconnects. This one's got a little bit more dirt on it.
Depending on how encrusted yours is, this may take a little while.
Because let's face it it: gets a little muddy back here.
So what we are looking at here are two plugs: there's one with two wires, and then there's
one with three wires coming out of it. Now this one with the two wires, that's actually heading
up to our battery. The one with three all the same color-- they're yellow-- those are the three
phases that are coming out of the stator and the rotor which is down inside of the engine.
So what we're going to do is set our meter to AC volts which is the V with that little sine
wave over the top of it. And what we're going to do is go from phase to phase.
So we're going to go from 1 to 2, and then 1 to 3, and just for kicks we'll go from 2 to 3. And
those three measurements that'll tell us if we're getting an AC voltage from each winding inside of
there, which there are three separate ones. Now at idle, it'll have a AC voltage somewhere between
18 and 22, somewhere in there. Of course if I rev it up, it will go a lot higher. But just having
it at idle it will give us an indication as to whether or not it's producing AC volts. 18,
18,
18. So I think we've pretty much found our culprit, and what we can do to verify is I'm going to go
ahead and remove this regulator rectifier. That's held in by just a couple of 10 millimeter head
bolts. And I'll show you a couple of static checks we can do with the volt-ohm meter
to see what's going on. Now is it really important? Not, not really, because
we know it's got a good battery. We know it's getting an AC signal from the stator in the rotor.
So it's going to be the regulator rectifier. Now the technique I'm about to show you really only
works on this one particular regulator rectifier. We have a video that shows the different
variations that you can run into depending on which manufacturer you're working with. Is this
really necessary? No, I just want to show you what's going on inside of this one. We're going to do a
diode test, and you need to make sure your meter has that little arrow with a line in front of it.
That is the the sign for a diode. What we're going to do is electronically look inside
of this particular unit, and we're going to either forward or reverse bias the diodes
inside, and that'll tell us whether or not that they're in good operating order. Now is this an
absolute as far as determining if your regulator rectifier is functioning or not? No, it's really not.
We've actually already proven that, but if you see an open or close and what I'm about
to show you, well, then that absolutely confirms that there's a problem going on inside of it.
So we're going to do a forward bias first. So we're going to put
our negative here, and then we're going to go to each one and we should see a 0.5. 0.5,
0.5, 0.5. Now we're going to bias the other set,
and then we take our positive to this terminal. And we should see a 0.5 going across each three again.
We're good there.
Nothing there. 0.5 there. So believe it or not, this one was probably charging a little bit,
but we have a burnt diode on that one particular part of the network.
So I'm betting once we plug in that new one, it's going to start charging again.
I'll tell you what: to make this a little bit easier, I think I'm
going to go ahead and plug in the wires first,
then mount it.
Okay. Now let's crank it up one more time and see if she's actually charging.
Bring it around to DC volts.
We're starting out with a static voltage of 12. 1.
There you go, 14. That's what we're looking for.
All right guys, that's gonna wrap this one up. Listen, if you have any questions or comments,
why don't you leave in the section below and I'll do my best to answer them.
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keep up with whatever I'm working on next. We just want to say thank you for shopping here
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