Why won’t Bandit 1250S start on the button?

Q. My dad has a Suzuki Bandit 1250S on an ’07 plate and it’s 50/50 whether it will start each time he thumbs the button. He’s replaced the battery but it’s not turning over at all.
Suzuki Dude, MCN forums

A. If the regulator/rectifier is behaving itself and all the fuses are in working order, take a look at the starter motor.

The magnetic strips in the case can come off and get chewed up. There are plenty of used ones out there, which is good because a new one would cost about £450.