No-one seem to have a diagram on the repeater but I did find this on the web. (see the link Below) Scroll down to the bottom of the page and you will find photos of how this guy put his back together.
Yes it will sting or possibly injure the animal. Even though it's a relatively slow firing pistol. 200 FPS. The pellet will sting if fired a a close range. If you hit a rodent or very small animal it...
Do not use regular oil, only use Crosman Pellgun oil or RWS pellgun oil. It can be purchased at most sportingoods shops that sell pellet guns. You can also order it online (See the link below.)