This does sound very, frustratingly, familiar, but the nearest i can think of at the moment,which certainly doesn't fit exactly-there's a motorbike accident and the man who finds the female amnesiac pretends he's her boyfriend- is The Red Sqirrel(Medem), Spain,1993.However,i'm sure i've seen a film which fits your description better.If it's not The Red Squirrel you're thinking of, i'll try to come up with the right one soon. 