The accident involving a North Yorkshire Fire and Rescue Service vehicle happened on the A170 near the village of Wilton, between Scarborough and Pickering, at 2.30pm on Saturday.
The Honda motorcyclist, who has not been named, was treated by paramedics but he was pronounced dead at the scene.
Four people in the fire engine, which was not on an emergency call at the time, were uninjured.
The vehicle was returning to its Scarborough base after being sent to Kirkbymoorside to cover crews involved in the weekend flooding alert.
The road was closed for about five hours for police investigations.
Another motorcyclist was killed in a separate crash at about 5.20pm, on Friday, when his green and black Kawasaki bike collided with a tree branch which had fallen into the road.
The Great North Air Ambulance was called to the scene on the A66 near Scotch Corner in North Yorkshire, but paramedics were unable to revive the 42-year-old motorcyclist, who was from the Sheffield area.
And in a third fatal accident, a motorcyclist in his late 30s from the Selby area was killed when a red Suzuki bike crashed into the central reservation on the westbound carriageway of the A64.
The crash happened at about 11pm on Saturday night at the Grimston Bar slip road on the outskirts of York.
A pillion passenger was also on the motorcycle, but North Yorkshire Police has not released any details about them.
The number of deaths on North Yorkshire's roads rose in 2007 despite safety campaigns being run by the county's emergency services.
Last year's death toll was 81, an increase of 12 on 2006, although the figure was slightly lower than the average for the last five years.
A total of 727 people were seriously injured in the county last year, down by 69 on the previous 12 months.
The 95 Alive partnership – which includes North Yorkshire Police, fire and rescue service and local councils – expects to meet its target of keeping an extra 95 people alive between 2005 and 2010.