My wrenching skills are basic, but I'm always ready to try and learn. So I post this here, where some other rider may learn as well.
Late last season the bike ('09 Gen 1 Versys with 60,000kms) started acting up. The bike was getting hard to start, especially from cold. I had to push the starter for 3 or four cranks. The idle was rough. A couple times it stalled at idle. Sometimes the dash lights did weird things when I turned the key to "on". And the headlights and dash lights faded and flickered, especially at idle.
The battery was less than 2 years old. I was starting to worry that I was having stator trouble and my charging system was screwed. I messed with the idle to try to stop the flickering lights. That was not a solution.
As it was late in the season I parked for storage and removed the battery as usual - stored on my work bench in the house. I took care to keep the trickle charger on more during the Winter.
Spring came and I re-installed the battery and started riding. It seemed better. It was not so hard to start and the light flicker seemed to be much less. I got the idle to where it should be. For the most part, the bike was running just fine. But, each day seemed to get a bit worse and after a few weeks it was just like last Fall. All the same symptoms and was convinced I was in for an expensive repair.
Today I had a particularly hard start on my way out for gas and errands. After fueling I went to re-set the ODO, only to see both ODOs had re-set themselves and the clock was wrong. Damn, the battery had dumped itself out since yesterday? Time to solve this.
I consulted with a neighbour buddy who rides and we put his volt reader/charger on. The battery looked OK. 12.2 V, dipped to 10 V on start up then rose to 13-13.5 V running. Alternator reading was over 13.5 and rose on higher revs. Another riding buddy from across the street noticed the mechanical ritual occurring in my garage and joined in. He brought his volt meter over to double check numbers. Everything seemed to indicate that the battery was fine and the charger system was working.
To prove I was not crazy (or too crazy) I was trying to demonstrate to my compatriots that the lights do flicker when it's warmed up and at idle and I also turned the bike off and re-started it a couple times in the process. One of those times the dash did that weird thing - blank - with the key on. So I reset the key and hit the starter. It was at this moment one buddy said "The battery arced". Trying to find the dark corner of the garage to demo the dash light flicker, he had caught the light of a spark across the negative terminal.
It was loose. Way loose. I undid the leads and pulled the battery. Evidence of arcing - divots - were on the terminal. And, it could all do with a clean up. Took a wire brush to all the contacts, re-installed and made sure it was all good and tight, and BAM!
The difference is night and day. The bike starts and runs like I just rolled it off the showroom floor. I do 360 degree tight checks all around the bike a few times a season, but I never thought to check or tighten the battery leads. I never cleaned them either.