Mine was stucked as well, I made a combination of two wrenches (in order to have more torque) pushed down and at the same time had my brother tapping the bolt with a bar and a hammer, after the second tap we heard a CLICK noise, and then the screw started to come out.

On another ocassion, the same kind of bolt was stucked on the transmission of my car, therewas no way to remove it, so we fill it with some oil and took the car to the mufflers shop, they heated the bolt with the acetilene torch, and then put a breaker bar on it, took no time for that to become loose.

Try to remove it as everyone has suggested, if not possible, just remove as much oil as you can either with the vacuum suggested method, or by opening the left cover, put new oil on the bike, and later on take it to somewhere with more tools that can apply heat and more torque on it.

Good luck!