Never owned a skid loader before but now get the fun of learning. BTW someone has replaced the Onan engine on this one with a Vangard 18 Hp. Anyway did some minor repairs and fixes, but now in the process of cleaning the chains, adjusting and oiling. I can see some access back under the seat but not enough to see the chains or clean as needed. I am sure others have cut access holes with either a large hole saw or a metal cutting saw such as a Sawzall with a good metal cutting blade. Any tips on how large to make the hole or about where to start cutting? I know there is a gas tank back there and I hope I'm smart enough no to get into that. Any suggestions??