Bad Rectifier? That's what I thought... By jstluise (Read 10,268 times)

[jstluise]

I have a Kymco Agility 125 (125cc GY6). I'll try to keep this short...

My original problem was an unregulated and high charging voltage (~17-20VDC). My battery was fried because of this. My initial thought was a bad regulator.

I picked up two replacement regulators off eBay (specified for the 152QMI engine) and neither of them solved the problem.

I checked my charging coil and lighting coil resistances for the stator and they are right at the upper end of the spec in the FSM. So I think I am good there.

I really don't know what else to test.

One thing I found odd is that my blinker relay is buzzing and making funny noises (not a normal sound) when the DC voltage is high. Looking at the wiring diagram, I don't see how the blinker relay can do anything when the blinker switch is off. And I don't see how this could be causing my problem, but it is weird.

I'm really at a loss and was hoping someone can shed some light on this.

[Alleyoop]

If the relay is buzzing it is toast, take it off and go to the autoparts store and get another one 12v and with the same number of connectors some come with 2 and some 3.
Alleyoop

[tvnacman]

6 and or 8 coil stator with 4pin head ache. You can keep what you have and install a ballast resistor. Or dump what you have and go with a sure thing, 11pole stator with fly wheel and 7pin regulator. I have all the parts for both tested and ready to go. How many wires are on the flashes. I know I have a 3 wire flasher, I will have to check on rhw two wire flasher.
Welcome to the forum!!!!!!
John

[Bashan]

Check the charging and lighting coils seperately by removing the wire from the R/R. Then set your multi to AC voltage and check to ground with some RPMs. The stator may still be hinky in spite of the ohms testing. Rich

[jstluise]

Thanks everyone for the responses. Finally a forum where I don't have to wait a week to get a response!

Alleyoop, I thought the relay might be toast. Didn't really think about removing it when I was troubleshooting. I don't see how it could be causing my main problem, but who knows... I was planning on getting an electronic flasher relay (load-independent) so I can switch out my turn signals to LEDs. I guess now is the time.

tvnacman, I threw around the idea of upgrading to the 11 pole stator, especially since I want to run a 35W auxiliary light in addition to my main headlight. But, for now I just want to get it back up and running...I've been without it for 3 weeks. The flasher is a 3-wire.

Bashan, I did perform this check. At an idle, my lighting coil put out around 18 VAC and my charging coil put out around 22 VAC. They increased with RPM, but I went easy because I didn't want to blow any of my lights out (I did blow my tail light, though). I couldn't find any specs on what they should be...what VAC should I expect from each coil?

With my regulator plugged in, I get around 8 VAC on my lighting wire (yellow wire). These seems about normal based on the brightness of the lights running on AC. Shouldn't this be closer to 12 VAC? Maybe this is why my headlight has seemed so dim. It's been like that since I got the scoot.

When I get home, the first thing I will do is remove my flasher relay and try everything out again. I doubt it could be causing my problem (I think it is more of a result of the problem), but it's worth a shot.

[Bashan]

Those stator voltages are good. Are you sure you have the right R/R? That 8 volts should be about 12. Kymcos are a different breed, there might be another component in the mix that needs a specific Kymco regulator. Rich

[jstluise]

May 9, 2012 15:19:19 GMT -6 Bashan said:

Those stator voltages are good. Are you sure you have the right R/R? That 8 volts should be about 12. Kymcos are a different breed, there might be another component in the mix that needs a specific Kymco regulator. Rich

Hmm, I guess I just though a 152QMI (125cc GY6) was used all around...didn't think there would be any differences. Looked into getting a Kymco R/R, but the local dealer wanted over $80. I picked two up on eBay for $8.

I get the same results with my original R/R and the replacement R/R.

As far as the 8VAC, I think this is all I've had since I've owned the scoot (bought it with 600km, has 8000km now), based on the brightness of the lights. I never did measure it though. Heck, I just found out a couple weeks ago that some stuff actually runs on AC!

Oh, and this leads into another question/problem I have. In my Kymco FSM, there is a testing procedure for the R/R where you measure the resistances between certain leads on the R/R.



I can't get any resistance readings on my original or replacement R/R. This is a simple resistance test, so I can't see myself screwing it up. Any idea on what's up? Couldn't really find anything online about doing this sort of test.

[Bashan]

We've pretty much determined here on the forum that those resistance tests on R/Rs are useless. Those charts are from the old manuals and to make a long story short, they don't make 'em like they used to. Each manufacturer of R/Rs uses different components to acheive the same functionality so they all test out different. A lot of them have circuits that won't let you get a test at all, as you've discovered.

I'll do some research on your bike and see what I can come up with. So what's the history on this, it was charging fine and then boom, roasted your battery? Or did you change something and it happened? Rich

[tvnacman]

I made a chart on a working 4pin regulator. It is in my photo bucket I Will post it when I get home. I can't seem to post links from my android.

John

[jstluise]

May 10, 2012 8:57:13 GMT -6 Bashan said:

We've pretty much determined here on the forum that those resistance tests on R/Rs are useless. Those charts are from the old manuals and to make a long story short, they don't make 'em like they used to. Each manufacturer of R/Rs uses different components to acheive the same functionality so they all test out different. A lot of them have circuits that won't let you get a test at all, as you've discovered.

I'll do some research on your bike and see what I can come up with. So what's the history on this, it was charging fine and then boom, roasted your battery? Or did you change something and it happened? Rich

Good to know. So for the history: Everything was going good until my battery started to become weaker and weaker. Had to kick start it on several occasions. The battery was new when I bought the scoot from the PO (about a year ago), so I thought maybe I wasn't getting a good charging voltage. After checking the VDC I found it to be high and unregulated (16-20VDC). So, basically my battery was being constantly overcharged until it gave out.

I drove it almost every day for about 6 months after I got it, then it mostly sat for 3 months (driven 3-4 times/month). Started riding it again and then discovered this problem.

I did experiment with adding an auxiliary light (35W) in addition to my main headlight (35W). I remember measuring the VDC to see the drop before and after I added the light. If I remember right, the charging voltage was around 12.5VDC stock (w/o adding the light). It definitely wasn't above 13VDC. I ran the light for a few rides, but took it off after my charging system couldn't handle it (battery was being drained after riding with it). Not sure if that little amount of testing triggered my issue. Regardless, I think something was up since my charging voltage was low and not closer to 14.4VDC.

On the same note, right after buying the scoot I noticed my starter didn't have the oomph that it normally had, especially if the motor was on the compression stroke; there would be a slight hesitation as the starter overcame the extra force. It never got worse and never had a problem with it not starting, so I didn't think much about it. When I put in a fully (bench) charged battery, the starter had A LOT of power. So, I think my battery wasn't getting charged fully due to the low charging voltage.

I drove it for quite a while after I played with the auxiliary light, so I can't say if the problem started right after that.

Sorry for the long message...trying to remember as many details as I can.

[Bashan]

I read your post, it wasn't that long, no worries. It sure sounds like that extra light roasted the R/R. However, if you're sure you have the right R/R replacement then it must be the stator even though the voltages are OK...it happens. Can you unplug the stator and check continuity between the yellow and white wires just for the hell of it? Rich

[jstluise]

May 10, 2012 16:28:07 GMT -6 Bashan said:

I read your post, it wasn't that long, no worries. It sure sounds like that extra light roasted the R/R. However, if you're sure you have the right R/R replacement then it must be the stator even though the voltages are OK...it happens. Can you unplug the stator and check continuity between the yellow and white wires just for the hell of it? Rich

I don't know how much more sure I can be about getting the right R/R, unless, like you said, Kymco is a special breed. Using my DMM I could get a forward voltage drop reading using the diode function only on one set of particular pins; both replacements I have matched, and the drop on the original R/R was a little higher...but I can say they all behaved the same as far as only getting a drop across a specific set of pins.

I'm not sure where the stator plug is (I think I have to remove some of the body), but looking at the wiring diagram I can isolate the stator by unplugging the R/R and unplugging one of the main wiring harness plugs. This is how I checked the charging and lighting coil resistances. I will check the continuity between the two stator wires and report back.

Do you know what the current rating on the R/R is?

Attachments:

[Alleyoop]

· Take the white wire off of the R/R, set your multi to AC voltage and hook one probe up to the white wire and ground the other. Start the scooter and give it some RPMs, you should get about 20v AC. If all your grounds and wires are good then you have a bad stator. Reattach the white to the R/R.

· Do the same to the yellow and you should get about 15v AC. If not, you have a bad stator.

· Reattach the yellow to the R/R and test it by touching one probe to an exposed portion of the yellow and the other probe to ground. With scooter running and some RPMs you should get 12v AC. If not you have a bad R/R, it's not regulating the voltage for the headlights etc..

· Do the same to the white and you should get 12v AC, if not you have a bad R/R. The voltage is regulated to 12v AC on that side of the R/R but is still not rectified for DC voltage to the battery.

· To check the rectification set your multi to DC voltage and check the red wire off of the R/R by touching an exposed portion of the wire, even at the red battery terminal, with your red probe and grounding the other. If your stator was pumping out white 20v AC on the previous test and you're not getting 12v DC on the red wire after all of the above you have a bad R/R. It isn't rectifying or regulating the voltage to 12v DC.

Alleyoop

[jstluise]

I just got done with some testing. I removed the faulty flasher relay and did everything without a battery installed. The flasher relay must have been shorting the system because removing it changed everything.

I did check for continuity on the stator (white and yellow wire) and there is continuity. Got about 1 ohm.

May 10, 2012 23:06:02 GMT -6 Alleyoop said:

· Take the white wire off of the R/R, set your multi to AC voltage and hook one probe up to the white wire and ground the other. Start the scooter and give it some RPMs, you should get about 20v AC. If all your grounds and wires are good then you have a bad stator. Reattach the white to the R/R.

· Do the same to the yellow and you should get about 15v AC. If not, you have a bad stator.

See this post until after the test...I will do this next time.

· Reattach the yellow to the R/R and test it by touching one probe to an exposed portion of the yellow and the other probe to ground. With scooter running and some RPMs you should get 12v AC. If not you have a bad R/R, it's not regulating the voltage for the headlights etc..

I got ~12VAC at idle and up to 14VAC at a high rev. Is this range good?

· Do the same to the white and you should get 12v AC, if not you have a bad R/R. The voltage is regulated to 12v AC on that side of the R/R but is still not rectified for DC voltage to the battery.

Got about the same; 12-14VAC.

· To check the rectification set your multi to DC voltage and check the red wire off of the R/R by touching an exposed portion of the wire, even at the red battery terminal, with your red probe and grounding the other. If your stator was pumping out white 20v AC on the previous test and you're not getting 12v DC on the red wire after all of the above you have a bad R/R. It isn't rectifying or regulating the voltage to 12v DC.

So, for this test I was only getting 6.5-8VDC, depending on the revs. Not good. Now the odd part: I switch to VAC and got ~14VAC (at idle) on the red wire (which goes to the battery). What?!

I did all these tests with my original R/R and the replacement R/R; all results were identical. Also, I should note that no lights (well, just the small instrument panel lights) are running off the AC during testing (my tail light is blown and I had the headlight removed).

[tvnacman]

The diodes in the regulator maybe shorted as a result of the bad flasher. You need to keep the bad flasher out of the system and you need a good battery connected. Then check the system again. The battery acts as a filter/capacitor to smooth the ripple .

John