the two caps you poped off and didnt see anything are coolent passages. the blaster motor first was designed as a liqued cooled motor for the dt200 dirtbikes. when building the blaster they used the origional block of the dt with minor differences and installed an aircooled cylinder on it making the blaster motor.
there should be a little round glass window on the bottem right side of the motor. thats how you check oil level. theres two lines beside the glass that shows low and high and the oil should be between. its sometimes hard to notice where the level is just clean the glass up and lift the blaster up on the right side and you should notice the level move abit.