Well here's kind of a new one. Let's see some ideas as to what might be going on. A buddy of mine has a 2008 Heritage. A couple of months ago he put a new battery in it because the old one was getting tired. He's not experienced any kind of problems since. He rode the bike to work yesterday and all was fine. Then hit a club on the way home. No bike problems so far. When he started the bike up afterward, the idle came up to about 1500 rpm and stayed there. He then stopped to pick up a six pack on the way home. When he went to start the bike all that would happen was the starter would click. His lights were fairly bright though. He couldn't get it started so he left the bike there overnight. I went and jumped him off this morning, but before I had a quick look at it. Lights were bright and the starter only clicked. I jumped the bike off and his idle speed came up to about 1700 rpm and stayed there. While it was warming up his headlight starts to flicker and went out. We were only a few miles from his house, so he rode it home. By the time he pulled into the driveway, his idle speed was up to 2500 and stayed there. The head light was still out and the lights were dim. He shut if off and the battery was completely dead. He also said his engine light came on while riding home.

So, what do you think might be up with his bike? Running good in the morning to fast idle, to dead battery, to faster and faster idle and headlight going out and then the engine light coming on, all in a matter of a few hours..

 

Have the new battery and the charging system checked. Make sure the stator is making the proper power and the regulator is doing its job first. If all that is working properly you need to start checking sensors, head temp, IAC, CPS, etc. A shop with Centurion Pro diagnostic capabilities can check all that stuff for you if you don't want to take it to the dealer...

 

He's at the dealer explaining all this to them as we speak. A stator will usually warn in the form of an engine light. Except for the short ride home this morning, he's not had any lights. He also put a new stator in it about a year and a half ago. That doesn't mean it hasn't gone south though. The real curious thing is the ever increasing engine idle and the headlight going out. That's a new one on me..

 

Certain conditions have to be met before a code will set. A code will not just set in a instant. One of the main causes of a stator failure is a weak battery that won't reach a full state of charge, and causes the charging system to overwork and fail. The old "weak" battery could have caused this.

 

Well a little update on my buddy's bike. He had HD pick it up to see what the problem was and fix it. They charged up the battery and checked the stator and regulator and all is fine. Load tested the battety too. They also checked it for current draw and that was good. So he picked it up this afternoon. He rode exactly 9 miles to a gas station, filled it up and when he went to start it the bike it was completely dead again. He said that after he left the dealer the idle progressively increased again and was back up to about 2000 rpm by the time he got to the station. Well, HD is on their way to pick the bike up again. I can't think of anything, including a bad stator, that can kill a battery in 9 miles other than some kind of a dead short. That doesn't explain the rpm either.

When my stator died completely I made it 55 miles on a half charged battery..

Also, guess we're not going the the Louisiana HOG rally on Friday..

 

Sounds like a loose battery cable.

 

Nope, they checked that too. He did have his electrical accessories attached to the battery first with the main cables on top, but they fixed that; so that the main cables are first on the battery.

 

Ok, it looks like the final verdict is in. It looks to be the voltage regulator. It checks fine when the engine is cool, but when it gets up to temperature, it not only stops working, but goes directly to ground (dead short). That explains how the battery would drain so quickly. Also, the ever increasing rpm is caused by the very low battery voltage. At such a low voltage the ECM apparently loses its mind..

 

Glad they found the problem. Hopefully, your plans are back on schedule for tomorrow.

Does he have a chrome voltage regulator? When I went to purchase one, the parts employee told me they tend to run hot and have a greater chance of failing. He recommended the chrome cover and I heeded his advice. I appreciated his honesty.

 

No, he has the standard regulator with the chrome HD cover/surround, just like I do.