Replacement Regulator No Good?

[rocksandhammers]

So as a continuation of my previous post I ordered a new regulator off eBay to replace my faulty one. It’s not oem, but it looked like the same design and it said it was right for my model (https://www.ebay.com/itm/Regulator-For- ... nav=SEARCH). It came in this afternoon and i got it in place and ready to hook up. While I waited on the battery to charge to 100% I decided to test the diodes in the new regulator. All of them were fine except for the b/w-b/r which was at 1.1 v. Manual says it should be 0.4-0.7 v, and the one I just replaced was closer at 0.85 v. Did I get a shitty replacement part? Figured I’d ask before hooking it up and trying to ride on it.

[hillsy]

Shunt style regulators are pretty much all the same - the main difference will be the plug / wiring and the charge / amp ratings.

Best thing to do is just plug it in and see if it works.

I got a $20 one for my LC some years back and it worked fine.

[rocksandhammers]

Yeah. Everything looks the same. Even the wire colors. I just wasn’t sure since testing it showed it even more out of spec than the one I replaced.

Best thing to do is just plug it in and see if it works.

So if I hook it up and the charging output is 14-15v at 5000 rpm it should be good to go?

[hillsy]

Yep - if it does that it means it works. Just make sure it doesn't charge over 16v or you'll fry things.

[rocksandhammers]

Alright. New regulator is installed. Threw the battery in it and started it up. Read about 14.2 v. Started revving up to 5000 rpm And voltage never increased. There was a slight drop down to 13.8 or so when I let off the throttle but I expect that’s normal and it went back to just over 14 pretty immediately. Going to take it out for a ride first thing tomorrow. Thanks for the help hillsy.

[rocksandhammers]

Well, I think the new regulator may unfortunately putting off too many volts. Haven't had time to test the charging output yet, but on the way home today I blew the main fuse. Of course it happened on the one day I didn't have my tools with me, and I was out riding the back roads in the middle of nowhere. Used one of my free tows from the AMA and just got it home. The weird thing was it didn't even happen when I was really laying on the throttle or anything. I had been cruising at 50 mph just out of fifth gear and was slowing down at a stop sign when it blew. I had already ridden 60 or 70 miles today, and it has been over 300 miles since I put the new regulator on. Since the wiring diagram doesn't show anything else on that circuit other than the battery and the starter motor, I assume it's the replacement regulator? Guess I'll need to try and find a used OEM one online somewhere. Local bike shop wanted $230 for a new one.

[Herb]

Unless it is putting out a REALLY high voltage it should not blow a fuse. All of the fuses are after the battery and only blow with too much draw.

Fuses do fail every once in a while just from the number of power cycles.

Test the output and as long as it is less than 15vdc and more than 12.8 it should be good to go.

[rocksandhammers]

Hmmm. Alright. Since I just had threw the new regulator in it seemed too much of a coincidence to have the main fuse suddenly blow. But I’ll check the charging output again and report back.

[hillsy]

Fuses can break through age and vibration as well as load - do you know how old the fuse was? Have you ever changed it? Is it the correct amp rating?

I'd just change it and see how it goes. Maybe take some spares with you just in case.

If it keeps happening then something is wrong.

[Herb]

I had a GT550 that would blow the main fuse for no apparent reason. Sometimes it would go weeks with no problem, other times it was almost daily. I hunted for a short tearing wiring apart using a meter to look for a short to ground. I was almost to the point of selling it for junk. It got bad enough that I actually put a bolt in to replace the fuse figuring that the short would cause a wire to smoke, never had a problem in over 2 months. I replaced the bolt with a fuse and 3 days later it blew.
A light bulb in the tach went out so I went to replace it. On the bottom of the tach was a chrome cover held on with 2 nuts, the bulbs were behind it. When I pulled the cover off I found that one of the light bulb wires was pinched under it and was partially worn through the insulation to the point that 1 strand of the wire was touching the cover. After repair of the wire and putting it back together, making sure the wire wasn't pinched the fuse issue went away.
Since I had never had the cover off, I believe that the PO had probably changed a bulb and didn't realize that he had pinched the wire.

Point is that fuses blow for many reasons, including age and use.

[rocksandhammers]

Fuses can break through age and vibration as well as load - do you know how old the fuse was? Have you ever changed it? Is it the correct amp rating?.

Not sure how old it was but I’ve had the bike for three years now and I don’t think I’ve had to change that particular one, but maybe. I’ve had some blown fuses in the past. Should be the correct amp rating.

I'd just change it and see how it goes. Maybe take some spares with you just in case.

I almost always have a box of spares and the necessary bits to get at the fuse box with me. Naturally the one time I was lazy and didn’t grab my bag is the one time I needed them.

[rocksandhammers]

Finally got around to testing the charging output on the bike. Lo and behold the new regulator is already fucked. When testing the diodes one was already burnt out or something. Perhaps since it wasn’t working correctly it sent too high of a voltage through the system and blew the fuse? Seems unlikely they’re related at this point. Guess this is what I get for trying to get a new regulator for cheap on eBay instead of an oem.

[hillsy]

You don't need an OEM RR - a series regulator is a better option. Google Shindingen SH775 or Polaris. Even second hand is OK for them.

I'd be suspecting you have a wiring issue somewhere though to burnout even a cheap RR in such a short time.

[rocksandhammers]

Any recommendations what I should start checking? Haven’t really had any other electrical problems show up.

[Herb]

What is the voltage at the battery when running?
Was the diode shorted or open. If shorted it might cause an AC surge into the system. The output of the stator is supposed to be 80 VAC when read between 2 legs. If it is more than that it could burn out the diode but I would be more inclined to think that the diode was bad from the factory.

[rocksandhammers]

Voltage was 12.6 v while running. The diode didn’t read any volts going across it so that would mean it’s shorted right?

[Herb]

Voltage was 12.6 v while running. The diode didn’t read any volts going across it so that would mean it’s shorted right?

Actually, it means it is open if the meter reads 0 ohms in both directions.

[rocksandhammers]

Alright Herb, so I did some further research on open vs. short on a diode and retested it. I believe it's shorted. When having the multimeter in the diode test setting I got minuscule voltage in both directions (like 0.001V or less). When I have the multimeter in the resistance setting I was reading about 0.7 ohms in both directions.

[Herb]

A diode is like a one-way gate, current only passes in one direction. working properly it will read open ( like a broken wire), or close to it, in the other direction it will read continuity (like a good wire) or close to it. What you are reading is high resistance in both directions that is basically an open circuit where no current will pass. So yes, the diode is bad. It was probably faulty from the factory or when the thing was put together it could have a bad solder joint and it broke causing the high resistance.

If it were me I would make sure that the stator isn't putting out too high of a voltage by doing the stator tests that are in the manual. It is possible, highly unlikely, but possible, for the stator to be bad and put out too high of a voltage. Usually, a bad stator will short one leg to the ground or break a wire and either way the voltage on one leg will be reduced or non-existent. I did read of a case where one leg of a stator was putting out much higher voltage than it was supposed to but the guy that posted it never said what caused it.

[rocksandhammers]

Herb, thanks for all the great information. I’ll be sure to check out the stator before putting a new regulator in just to be sure. Wouldn’t want to screw up another one. It will be a few days before I can get a new one anyway.