That's from "I Fidanzati della Morte," a 1957 film. ("The Boyfriends of Death," or "The Couples of Death" as translated.)
It would be nice to see the whole movie, but I'm not ready to risk streaming it from an unknown site, which is all I could find. Apparently the Guzzi factory was used as a filming location in other scenes, judging from a comment.
Moto