Just buy another Kyosho chain and add as many links as you need. The pics I've seen show the stock chain has a "master link" (the one in your pic) which makes it easier. A chain tool makes disassembling and reassembling the chain easier but it can be done without one too. If you google "chain pitch" you'll find lots of links to determine chain pitch and how to work on a chain with and without a chain tool. This is an Rc application though so I doubt the chain was made to industry standard sizes but I could be wrong.