Heinz was giving me starting trouble a couple years back. Thought it was the battery. Turned out it was either corrosion in the starter button or the ignition switch. Cleaned both. She hasn't missed a beat since. I did pull the starter. Cleaned it up a bit. Have spare brushes on standby. I probably threw out a battery with a few years left in it because I was barking up the wrong tree.
My neighbour picked up an RS 1150. Came with a brand new battery installed. It's been nothing but a pain in the ass. You can get a bad brand new battery.
Good luck. Riding season is soon upon us!