“Bikers - people who ride motorcycles”
Bicycles were around first, so they get dibs on the term. There isn’t even a “bi” in “motorcyclist” anyway. Should be “mokers”.
That's just gay talk.
You’re close: In my earlier motorcycling days the big machines were just called “motors.” One of my even older friends ran whiskey with an Indian-—4 gallons at a time at 100 mph, he claimed, and his was a “motor” also. Mine have mostly been “rocket sleds.”