Hello, I have a couple of basic questions. First of all. How can I tell If im running a 525 or 520 chain. It seems my sprockets just have the tooth count. Now came to my attention during my last ride while off road and pushing it up hills it seemed the chain was kinking or slipping. The sprockets are in good condition. The chain is extended all the way with adjusters and has about 7000 miles of mixed riding. Plenty of water mud. So my last question is Is this a pretty easy job? Given I purchase the right tools. it appears the chain I have now has a master link. So if my writing does not confuse you completly please respond.