Read this section if you have not yet: Classic Instructions for Building and Repairing Motorized Bicycle Engine Kits - Motorized Bicycle: Engine Kit Forum
It will teach you a heck of alot and prepare you with the knowledge on what to do to the kit before you start to install it on the bicycle and a whole lot more.
Also, Norman has shared his wealth of knowledge with us in his own section:
He is a guru with these engines.
Each engine has it's own quirks, and they also share similar ones too.
Please don't hesitate to ask questions if you get stuck, and don't be afraid to use the search function either. I can answer alot of questions easier by searching for the answers and linking to the threads rather than typing out a long post.
Have fun, and be safe!