Mid May I left NY for Arkansas. By the end of the second day I noticed my voltmeter bouncing around just as you describe. When I pulled over for gas meter went back to 14. Once back on the highway the meter started jumpimg around again. When I got to Arkansas I had the electrical system checked by an indi and he said it wasw fine.

I've pretty much decided to just live with it the way it is.

Another shining example of HD quality. I wonder if the guage was made in China.

 

Update... problem fixed. New Voltage Gauge. $54 from the local Harley dealer. I looked at the connection on the old one and it looks like the positive connection had a small amount of corrosive dust on it. I believe it is made out of aluminum it was a white'ish discoloration... could not clean it off. Not sure if this was the issue but the new one both contact are shiney. Anyhow... was lucky this time.

 

With that logic you will fry a battery in no time. they won't take 16 to 18 volts for very long. Look at what you said or do the math.

 

mine was a loose positive battery cable,hasn't done it since

 

OK folks... new voltage guage... seemed to fix the issue... after another 200 miles the guage started bouncing again. Decided, screw it and bought a new battery... this did not fix the problem. The voltage guage is still bouncing after about 20 miles down the road when the engine get good and warm. Back to the drawing board for me. So far, New Voltage regulator, New battery, New voltage guage, all that is left is the stator. Taking this pig into the Harley dealer and have them do a full check on the stator... Something is just not right... I have even replaced all the relays on the fuse box... the bike runs fine... but this is just something that is blowing my mind.

 

My bike is in the shop right now for a charging issue, bike is fine until it warms up, voltage drops then engine and battery light come on, just had stator and battery replaced about 1100 miles ago, I told the dealer then they might as well replace the regulator also, no deal. Yesterday they called me and said the regulator is shot, lol. I'm glad it's all under warranty, I told them yesterday I believe it's the regulator that probably took the stator out the first time and they might want to replace or at least physically check the stator again to make sure it's ok, no deal, I won't be surprised if it's back in the shop again soon. As long as it's under warranty and they don't want to listen, I don't care, once the warranty runs out I won't be taking it back and any fix I need I'll do it and get it right the first time.

 

Professor, I'm pretty positive it has got to be the stator. A quick trick to tell if it is the gauge or the stator is to turn the bike off and tap on the face of the gauge. If the pin moves, its a bad gauge - if not, its the stator. Had the same issue with my 10 SG. Did the tap and it bounced, replaced the gauge (under warranty) and never another issue. That was at about 12K - still fine now at 28K. Good luck!

 

13.5 to 14.2 is optimal voltage .... anything below 13.5 indicates low output, and anything over 14.2 indicates overcharging. Of course low output leads to a discharged battery, while high output will eventually cook the battery. Overharging will cook the water in the battery and most batterys are sealed today so there is no way to add water. While an increase in the rpm's will generally increase voltage output minimally ( usually not much more than one and a half volts ) it is incorrect that the voltage will increase one volt for every 1,000 increase in rpm's. If that were the case you would be charging at a rate of approximately 17 volts at 80 miles per hour ( 2,900 rpm's on my scooter ). Some times erratic voltage can be attributed to a suspect battery. Be sure that all your connections ( especially grounds ) are clean and tight. Check your battery with a load tester ( this is the best way to effectively and accurately determine the condition of your battery ). Many times I have seen a volt gauge have readings different from what the load tester indicates. While my response may not address the OP's question directly I tought I'd address the response given by Akitakoi and try to clarify things. Hope this helps.

 

I am very interested in what fixed your problem. I have the exact same issue, sounded like you were riding my bike (2009 FLHTCU). I replaced the battery just because it is three years old, checked all grounds, wiring, and connections, all was good. I felt like the regulator was breaking down after it warmed up, but that didn't help. My shop voltmeter shows the charging system to be working right in all areas. I have ordered a volt meter to see if that will fix the problem. Please reply with a fix.

 

My 09 ultra is doing the same thing. Has the new meter fixed your problem?