This question has been raised and i will try to answer as best i can.
These groups were born out of the patchwearer, 1% ers, HA gangs in the 50's 60's era to the best of my knowledge.
Motorcyclists.....are those who ride motorcycles for leisure, fun, commuting etc
They are the straight up and down sect.They live a normal life like the rest of society. Motorcyclists are generally guys who go on the odd breakfast run, and commute on their bikes
Bikers.... are those who ride motorcycles and live the life of motorcycling.
They are defined by their colours and their affiliation to their club.
They are proud of their distinctive way of life and attitude to life.
Bikers commute almost every day, they go on rallies religiously, they commune in numbers on a regular basis, they have a strong brotherhood.
There is no divide between the two, more a lack of knowledge and understanding.
If anyone can add value to what i have said, please do.