Answer:
It depends on how many Bikes you have. You must have three, including a sergeant, to form a squad, which is 90pts.
However, the maximum size of a squad is 8 bikes and an Attack Bike. This is 255pts.
You can also upgrade the sergeant to carry special weapons, two normal bikers can carry special weapons, and the Attack Bike can carry a different heavy weapon. The maximum is 325pts, if you have all of the most expensive upgrades.
If you only have one, you may be able to use it as a Captain/Chapter Master on a Bike. It all depends on the wargear.