First off.. I've done all of the tests of the stickies and all pass... I have a brand new Harley battery also

Here's my problem.. This only happens on a hot day that I am tooling around town (stop and go)..

2008 Ultra all stock

Once she gets warm/hot and I come up to a stoplight with the brake on and the turn signal on, the volts will drop to @ 11 and pulse with the turn signal.. I can bring up the rpms and it comes back to 14.2 without pulse... I can turn the signal off and release the brake (no brake light) and goose it a bit and the volts will come back to @14.2 and stay at idle (headlight, passing lamps, radio on)...

When she is cool everything works as it should..

Any Ideas??

 

Sounds like either a bad connection in one of the battery positive or ground cables, or a thermal problem with the Voltage Regulator.

 

Battery terminals are all secure... Like I said it ONLY happens when it is hot

 

It's the regulator. Next time, bring it up to 2000rpm, if it reads OK, ignore it. It's not right but it will not hurt anything. Two things Harleys do not need is gages for Volts and Oil pressure. They will drive you crazy.

 

Yea.. If I am on the brake and the turn signal is on the volts will drop and the needle will pulse with the turn signal.. .If I bring up the RPM's it goes back up to @14.2v.. The problem with it not charging while hot at idle is with an Ultra there are plenty of electronics that need juice.. Just the Battery won't cut it..

 

On the early models (EVO) they all had 22AMP alternators in them and it was a certainty that if I switched on my passing lamps around town....I would get an engine warning light (EFI). As soon as I hit the highway at speed....the warning light would extinguish. It was a low-voltage code for sure. I believe all the recent bikes have the 32AMP alternators, or close to that.

I am struggling with a similar issue with a starter. Cold starts...not an issue, but as the bike warms-up and I make a fuel stop....it's a toss-up as to whether-or-not it will start. If I let it cool for 5-minutes....she spins right up. One can say they have cleaned the battery terminals and the "easy" stuff to get to. My test indicated a defective regulator, but I don't really think that's the issue. We'll see when I get another one in hand here to test, but I may very well have already solved the problem. I should know better as I am an electronics engineer by trade. I just overlooked and made some assumptions about some connections that I should not have made. I bit the bullet and totally disassembled every connection I could get to on the bike and found some serious corrosion under the starter cable. It was a hidden mess and there is no way to clean a bolted connection short of taking it apart.

Here is what that could mean. Current flow is determined by the voltage applied divided by the resistance in the circuit measured in ohms. If the battery cable and it's associated starter connection measures .5 ohms, the math tells you that circuit will flow 24 amps (12/.5). If that connection (circuit) measures as high as 1 ohm....your current flow becomes 12 amps (12/1). Just that small amount of connection failure will cut your starting capacity in half. Different metals expand/contract at different rates and I think that is/was my issue. I had a copper cable bolted to a copper stud with a steel nut....all full of corrosion.

Back to your issue....I once owned an 85 FXR and when you applied either turn signal...the bike would start missing. In those days they still employed the flasher to operate the turn signals. As I recall....the only way I ever fixed that bike was to install LED signals.

 

I'm sure it is not normal for the voltage gauge to drop while at a stop is it?

 

Well....yes it can be. It's already been mentioned that Harley gauges are pretty much "ball-park" in accuracy. It's not at all abnormal for the voltage gauge to drop at idle. It depends on what all you have energized at the time. The alternator is not going to do a great deal of charging until you get up around 2500 rpm's. ripsaw has likely said it in his post. Today's electronic ignitions are not going to function much below 12 volts. If the bike is running, I'd ignore it. But...I would take a good meter and measure the battery at rest (should be around 12.5 volts) and then crank it and watch the meter as the RPM's are increased. Generally speaking, you should see "around" a 2 volt increase across the battery terminals. That dashboard gauge can be off by a couple of volts either way.

I wanted an oil pressure gauge on an old EVO once and the mechanic refused to install one. He said...."all it will do is scare you to death anyway".

 

It has happened within the last week.... Up until then the volts kept a steady @ 14.2.. .This is a change in the readings.. I do realize that the idle gets a little low when the volts drop..

 

I agree that any sudden change can be cause for concern, but if everything checks out but the dashboard gauge reading....maybe the gauge could be at fault. I will say that while on a long trip some years ago, one of our riders gauges was reading close to 11 volts at idle, but there was no apparent problem with the bike, which was an EFI Ultra. Some 1,000 miles on into the trip....he lost his alternator (stator). It's not out of the question that you could have one going bad, but I would think it would be showing some continuity to ground when you tested the coils with a meter, not a dead short, but possibly a high resistance reading to ground. I had a stator go bad on a long trip, but it never actually totally failed. I detected a slight "new" vibration in the bike and told my riding buddy that something just was not right. We stopped by a river to do some sight-seeing and my scooter would not crank when we started to leave. In those days, I had a kick-starter on that Softail and it had points in the ignition. If it had not been for the kicker and the points....I never would have gotten home. It is entirely possible for a stator to be failing over time and not all at once.

Sometimes, you have to wait for total failure before finding out what it is, or start replacing parts until the problem goes away. You've replaced the battery. The next easiest choice is the regulator...then the stator. If it does this on a regular basis, I'd remove the seat-screw and have my good volt-meter with me. Pull the bike over, yank the seat and read across the battery terminals at idle. If the meter indicates something less than say....13.5 to 14 volts at normal idle, then you may have a problem. If it reads 14 or better, suspect the gauge.

Electrical problems can be very finicky. Interment and hard to catch in the act. In most cases, when a stator fries....you will smell it about as fast as you know it. Pull the derby cover and use your nose as a tool. If a stator is starting to fail or has failed, the oil will have a burned odor.