I still had my original battery in my bike from 7/07 until last fall. I have 72,000 miles on my bike and have used a battery tender since day one. I started noticing that while on a trip, and off the tender, the bike seemed to crank slower before starting. Also, even though i did the anti-backfire on deceleration mod successfully years ago, on decel on long hills, especially in 3rd or 4th gears, i was getting a loud backfire at times... I had just serviced the bike all connections were gone over on the battery, frame, and power commander. I found nothing loose or corroded.
I decided to be proactive and change out the battery before any real cold winter riding. Not only did the bike crank faster and start easier, when it jumped to life, it idled smoother at 1100rpms, seemed crisper with fuel delivery, and my backfire issue dissapeared. The C14 is a very electronic motorcycle.. If you still are running the OEM battery after 4+ years, do yourself a favor and change out the battery. Odd things happen to batteries over time, keep your bike running at its best.
JJ