I recently installed a scangauge ii on my 04 R50. It is showing at idle anywhere from 13.1 to 13.6v. With engine not running. It will drop to 12 4v . Even going down the road it never goes over 13.8v.
The reason I'm asking is the other day I was at a stop light an the car acted like it was going to die. Then picked back up
A short time later dis the same thing at a dead stop. I did notice that I would see the odometer start to ever so lightly flicker before it would stumble. The battery is a tade over a year old.
Any thoughts?

 

I would have your alternator checked. Either the alternator or regulator seems to be acting up.