My 06 Bob does this when it's hot too, esp in the middle of hot days during rides like you stated at gas stations and stuff. My battery is over two years old so I guess it's time to replace.

 

Motors have more static compression when warm and even more when hot. If ANY engine work done (different cams, etc.) - might be simply the norm. Stock starters are designed for stock configurations. I had similar issues when I did a big bore / cams - ended up putting in compression releases.

If plain stock, as said, get the battery load tested. Also, check the battery and ground connections. The battery connections are known to get loose.

 

Don't know where you heard that, but that is news to me. Mine is stock and nearly 4 years old and (knock on wood) has never failed, and I do not use a battery tender, never have. I don't do short runs as a rule, shortest is probably about my 20 commute to work.
Expected life of any auto.cycle battery is 5 years, unless it sits in cold weather a lot. My Sporty was another story since it was carb' winter months were hard on it.
But every other bike I have had, about 15 and counting, I have been able to get at least 3 years, usually 4 out of a battery before it starts showing signs.

 

My o7 bob does this as well. On hot days after refueling. Very inconsistant to...just enough to keep you on edge with the fear of being stranded at the pump!

A suggestion from a previous post was to always start from nuetral. Not sure why... but this has helped mine a bit!
Db

 

So I'm not alone here. I don't know if that's GOOD ... but it's nice to know what I'm seeing isn't just my ride. Since the issue that prompted me to start this thread it hasn't happened again. I also started another thread about something else i've noticed ... every now and then my headlights dim a little for a second then go back to normal. On that thread people have suggested I contact the dealer so i'm going to talk with them in the afternoon today. Perhaps I have a loose connection someplace and both "issues" are related? I'll talk with them today, no doubt have the bike looked at and let you guys know what happened. ............ I'm starting to seriously think there is probably a loose connection someplace because that could cause both issues.

 

a battery will normally discharge internally about 1% a day, so if you let it sit, either connected or not connected, it will likely be discharged when you want to use it. A 'tender' is not designed to be a 'charger'... you're much better off just leaving the tender connected to the battery anytime you're not driving the bike.
The alarm system is not supposed to draw any power from the battery when armed.
In fact, you can arm the security module, remove the battery for the winter, put it back in and it's still armed.
Average life expectancy of an OEM Harley (tm) battery is five years. Aftermarket batteries about 2 years. OEM vendor is Penn Battery, they also sell the same battery under the name "Deka" through tri-state battery. (www.tristatebattery.com)

Hogdoctor

 

A few things I've learned about starting high compression engines also applies to hot starts. If when you shut off the engine, you've got a piston sitting at bottom dead center compression, the intake valve which is normally open a certain amount of degrees into the upstroke, will bleed closed and when the piston comes back up it will
have much higher compression pressure to get past on that first stroke. The trick is,
after you shut it off, or before you hit the button to start it, drop it into second gear and push the bike backwards against the power stroke just until you feel the cylinder pressure stop fighting you and that's where the pistons are near TDC.. This way when you hit the button, then engine will have half a revolution to pick up some momentum before it hits that comression stroke, and the intake valve will not close early and cause that high compression hit. Another thing I've learned is if the throttle or enrichener is opened at all, the pressure is much higher. If you're in the habit of cracking the throttle open a little when you first hit the button, you're not doing your starter any favors. Let it spin up before cracking the throttle. Sometimes an ignition system will fire a bit before tdc when cranking, and either fight your starter or cause it to kick back. I have on occasion rewired the crank and run buttons to allow the engine to crank with the engine in the 'stop' mode, so the owner can get it cranking first before lighting off the ignition.

just things to think about....

Hogdoctor

 

If the problem is only when it is hot, I would have the dealer check the ignition timing. It coud be causing higher cranking loads when hot.

 

Going to the dealer to be checked next Tuesday! I'll let you guys know if they find something.

 

The word "tender" was mentioned at least twice. Hopefully this is a tender plus type charger, these will sense a full battery, stop the charge automatically and kick in automatically when it senses the voltage has dropped to a preset minimum, never a continous charge to cook the battery. AGM batteries are a peculiar but reliable breed. I read something the other day, Harleys operate the electrical system strictly off the battery, the charging system just charges, doesn't provide power to nothing else, unlike a car.