There is a sticky here in the EVO forum by Dr. Hess that explains electrical/charging system diagnostics. THEN....we have sticky's in the General Maintenance section of the forum...parts I and parts 2 that takes one through the process. Now, the difference could just be that an EVO is a different critter in some ways electrically, but I don't think so.

Would anybody help me out here and read BOTH sticky's in BOTH sections of this forum and draw a conclusion. My conclusion is that they differ. The reason this concerns me is that I became stranded at a fuel stop with my pants-down (so to speak) because my scooter just moaned and would not start. Just as I had the cell phone out to call the wife and plead with her to bring the jumper-cables, I hit the start button and she fired right off. I ride some 15-miles back home...shut the bike off and she fires right back up. This concerns me and I thought I may have a battery, alternator or regulator issue. I replaced the battery if for nothing else it was time....4 years old. I am an electronics engineer by degree and trade, so I know my way around volt meters and I have a good one.

Here is what I am getting to. The sticky's in the General Maintenance section state that if ANY voltage is present on either of the pins of the regulator plug, it's toast. Those sticky's (both 1 and 2) state that the voltage at cruising RPM (around 3000-3500) across the battery terminals should be 14.5..more or less. The best that I can do is 13.8, which seems to agree with The sticky in this EVO forum. I also have .254 volts present on both of my regulator pins. If I take the sticky posted in the Gen. Mtce. section as gospel....I have a bad regulator. If I take the sticky in the EVO section as gospel....maybe I don't have a problem. The closest HD bike I can get to that mimics my system is some 80-miles one way and I can almost purchase a new regulator for the same money as making that round trip.

Is there ANYBODY out there that can simply take their volt meter, unplug their stator from their VR and measure to see if there is any potential on either of the VR pins? I have (what I thought) was a good spare regulator, but it also presents a small voltage at the pins.

I am not confused. I am just reading two different sticky's that do not agree with each other. My bike is a 98 Road King with the stock 22AMP regulator.

 

Did you follow the test procedure in my sticky? If you passed, don't worry about it. If you didn't, fix what failed. My sticky is how I diagnose them and have been diagnosing them since the early 80's, and it works for me and others. These are Evos. Do what you want.

 

Are you having a charging problem?

 

---------------------------

 

Sometimes you find something that needs fixing, and sometimes you don't.

 

First of all....I never meant to insinuate one was wrong and one was right. Only that they differ. If the bike cranks every time and all is well....I suppose it doesn't matter.

My system passes the procedure outlined by Dr. Hess. It does not pass the procedure outlined in the sticky's part 1 and part 2 in the General Maintenance section. Do I have a charging problem....I don't know. I had a failure to crank and sluggish starting and began to diagnose the problem. Replaced the battery, cleaned all the connections and the bike cranks and runs fine. I am about to embark on a long trip and a fresh battery combined with a weak charging system will likely crank 40-50 times or more without issue until you get 1,500 miles from home. I am just trying to make sure I have a good charging system.

The conflict is that sticky's in the General Maintenance section indicate that any potential (voltage) at the VR pins with the bike at rest and the battery installed does not pass the test and correct charging voltage at around 3,000 rpm against a known good battery should be 14.5 +-.

My VR pins measure a voltage of .245 on each pin and my charging voltage at 3,000 rpm's across a new and fully charged battery is 13.8 volts+-.

I guess that until I find somebody that has actually measured their VR terminal pins and discover there is indeed a small voltage present at those pins with the bike at rest, yet they don't have (or never have had) a charging issue, I'll wonder about it. I have measured two VR's on EVO's and both have a slight voltage on each VR pin. This, coupled with the fact that Dr. Hess has never had an issue with his diagnosis, leads me to believe that the sticky information posted in the general maintenance section (and about everywhere else in bike forums)....is not necessarily correct.

I also understand that as a battery charges and reaches a full charge, the VR output will diminish....just like it will with a battery charger. I am probably on a witch-hunt that I don't need to pursue.

 

I'm not very good with words but you're right. You don't have a problem but when you go looking for one you'll find one if not imagine/create one. I think it's called whistling past the graveyard... your bike has a new battery and is running cherry? Thank the Lord and keep up your maintenance.
Have a nice, safe trip!
Tom

 

Understood....I've been around these things for 30-years. I think Dr. Hess hit on the problem I have in his first paragraph.....my multi-meter is too good. Most of the meters people have stuck in a tool box likely would never read a voltage as low as a quarter of a volt anyway. You have more measureable potential than that from your head to your toes as you walk across a carpeted floor.

Breaking down in civilization is one thing. Breaking down in Melton, UT on a holiday, or at Joyce's Store in Geraldine, MT is another thing altogether. If you have never been-there-and-done-that....you'll never understand why any small problem (perceived or otherwise) can be troublesome.

If one actually takes the time to read and ponder both sticky's, you'd understand why I asked the question. The correct answer is....the one that works is the correct one to use. I tend to think that if people follow the sticky's posted in the General Maintenance section....a lot of good voltage regulators get thrown away, or you never will find one that doesn't exhibit some leakage (no matter how small) at the VR pins.

 

" voltage as low as a quarter of a volt anyway"

My question was going to be what range are you using on the meter.

Gm service manuals read that there should be 0 voltage on a ckt. I had to get it through my redneck head to use an appropriate range. Have learned to skip the Auto range when needed

Sounds like ya got this one nailed down

Have a good trip WP

 

As you always should when voltage checking....start with the highest scale you expect to encounter. You would not want to check an outlet in your home that is suppose to be 120V AC with the scale set any lower that 200. Likewise, you would not expect to see anything much greater than 12V DC at the VR pins when consideration is given for the resistance in the wiring. My meter starts with a 2V scale and works up to 20, 200 etc. In this case, I start on the 20V scale and then drop a notch to the 2V scale. Two VR's that I have measured exhibit leakage. The one on the bike now measures .245V DC exactly on both pins. The (what I thought was and still may be a known good spare) measures .217V DC on each pin.

I wish I could come-by an internal schematic of the regulator. A simple diode (AC to DC rectifier) may-or-may-not have an infinite resistance in the reverse direction and they can exhibit leakage. There are also other components within that VR that come into play.

Most automobiles I've checked charged at a rate of around 14-plus volts. My tractor charges at around 13.8 volts (and it hasn't failed to crank in years). One has to also consider that as a battery charges, it "resist" further charging. If you connect a charger with a meter on it to a battery that needs charging...you will see the amp-meter start out at a high rate of charge....say 10AMPS maybe depending on what your charging and the quality of the charger. As the battery charges, the amperage indicated on the chargers scale will drop accordingly. When the battery is charged, the meter on the charger will read close to zero indicating that it cannot "push" any further reverse current into the battery. You can certainly over-charge a battery with a large enough charger. A motorcycle charging system should exhibit the same characteristics. As the battery charges, the voltage measured across the battery should drop to whatever it's full charge is as the VR cannot push anymore reverse current through it. The issue is the balance of actual usage by the bike, as opposed to what your trying to push into the battery. This is why I agree with Dr. Hess on the "range" of that measurement....13-15. A battery closer to a full charge should read close to it's ambient charge...or 13-or-so volts. A battery that is weak, or is working against a larger load, will read a larger charge voltage as the VR works to keep-up.

In a perfect world, once you crank any vehicle you could remove the battery completely. The alternator will take care of the load as long as you keep the vehicle running at an RPM high enough to produce the needed output to maintain what electrical systems need to be maintained. Unfortunately, most Harleys that I know about cannot do this. They depend heavily on the charging system all the time.

Let there be no doubt here.....I am in agreement with Dr. Hess and not so much with the "other" sticky. To say that the charging voltage HAS to be 14.5-14.7 is not necessarily the case. It may just work out that way on some-or-most bikes, but it all depends on the needs of the battery as a result of current-draw.