Predator is the brand name of the engine line from Harbor Freight. They have them in different sizes based on Cubic Centimeters (CCs). They range from a 99cc to a 420cc engine. The 99cc Predator is not for sale in California. They do sell a pump with a 99cc engine. However, I am unfamiliar with it. The Harbor Freight website states that it is EPA approved. It doesn't state CARB approved. I do not know if it is for sale in California. It may or may not work for a motor bicycle project. I am sure it has a govenor.
Hiefy, Harbor Freight has two stores in the Reno area if the 99cc predator engine is the one that you want. I would call the store first to make sure they sell them and that there in stock. Have them hold one for you. I wouldn't let them know your from California. It is a least a 2.5 hours from where you're at.
Surplus Center has a 5.2 cu in. (97cc) engine that is CARB approved, but does have a govenor. Again, I am not familiar with this engine and know if it is applicable to motor bicycles. It is more than the 99cc Predator.
Surplus Center - 2.5 HP POWERPRO RS ENGINE CARB & EPA COMPLIANT