My motorbike (Triumph Street Triple R 2013) has an interesting issue. When measuring the battery, it constantly is over 12.7v or even higher. And it starts the engine super well when cold. The problem comes after a 30 min ride - if the motor dies, it struggles to turn the engine on again. Like, it will maybe rotate it for two seconds before stopping, as if it was drained. Wait a couple minutes and it will turn the engine on, but strugling (I have to open the throttle a little bit for it). Wait 30 min, it seems there was never an issue, and the engine will start effortlesly.
Just today I let the engine die going up my driveway ramp, and I couldn't start it again, as usual. 5 min later I managed to start it again with certain difficulty (again, as usual). I turned it off and connected a multimeter to the battery, and while it shown 12.6v (if I remember correctly), it lowered to 6v while cranking (it successfully started the bike though).
It shows over 14v while the engine is on, and it stays at this voltage even while revving.
I guess the battery is at fault here. I'm just curious why it won't work specifically after using the bike for more than 30 min: shouldn't it have more charge at this point?
