ISTR that the constrction of #25 is different from, e.g. #35, so chain wear and stretch will always be more of a problem, so the first alternative to consider is larger chain. For karts, of course, #25 is traditional, so all you can do is use better lube.
A search for "roller chain tools" without the quotes was productive, and suggests that you expand your inquiries to include Sears and Amazon, as well as chatting up your local motorcycle dealers.
That said, the tool business is such that only a few people actually make a given tool, and everybody else resells it, so you won't see much variety, other than cheap copies, which deserve some respect for their fragility.
Also, roller chain is (nominally) simple, so I would be surprised to find any tools that were terribly expensive, or especially, electronic. If you could describe your specific needs in more detail, someone might be able to suggest a tool from another trade that would help, or suggest a way to make a custome tool for your operation. That latter is more likely if there's a hint of a market.
Mike Halloran
Pembroke Pines, FL, USA
