Starter Motor Help

Hey guys! I have a 1995 Vulcan EN500 and I need some help removing the starter motor. I fully charged the battery and tried to start the bike, after sitting in storage for the winter, a few days ago. When I tried to start it the relay would click rapidly but engine would not crank. So, I started trouble shooting. I first took the battery to an auto repair shop and it tested healthy. I then thought that it might be the relay, so I bought a new one on eBay. Now when I hit the start button there is a single click from the relay, but still the engine won’t crank. I started checking the battery cables and notices that there is rust on the starter motor where one of the ground cables is connected. So now I am trying to remove the starter motor to clean the rust off and to test to see if it is functional. However, now I have run into a problem with removing the left engine cover. I have removed all the 8mm bolts, but it will not budge when I pull or twist on it. It there something on the inside that I am missing? I looked at a free service manual for a 1996 Vulcan, but couldn’t find anything different for what I am already doing. I started doing my own repairs about a year ago to help save money and due to the fact that the nearest motorcycle repair shop is 20miles away. Any help would be appreciated.