I reckon if you live, breathe and eat motorcycles ( thats not plastic ones ) than I would call you a "biker".
Our members here are all "bikers".
If you are in a club and terrorise others and distrubute drugs and murder and pillage, I would say you are a "bikie".
If you ride "plastic" bikes and ride to go really fast and do wheelstands at traffic lights, I would say you are a "bloody idiot".

Thats my opinion and I believe everyone is entitled to my opinion!