Yes I believe I do know. First remove the rear wheels then remove the the wheel nut ,then the 2 screws on the hub. It should slide off then. I don’t know if you know that there a number of disc in that hub. It’s a pretty cool setup. Back to the oil,my engine has a drain cock on the right side of the engine down by the oil pan. That will drain the oil if over filled. What kind of carburetor is used on your engine. Thank you for the pictures of the top.