I had a KMX125 do that once. It turned out to be the kill-switch, which hadn't worked at all for the preceding 6 months, and only did sporadically after this event.
Still, I had a pleasant 1/2 hour in the pub contemplating the situation & canvassing opinions from the locals. A bloke with a KMX125 solved the problem and gave me a good tip on a shortcut home.
Happy days....
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