The solution is to use a combination heat-shrink/solder connector. These connectors combine a small piece of heat-shrink tubing with a ring of low-temperature solder. You slip one over the splice and then heat it, preferably with a heat gun, but anything from a torch to a lighter will work just fine. As the heat shrink contracts, the solder will melt, securing and sealing the connection. These things are sold in just about every auto-parts store in the world, and a dozen of them should take up no more space in your saddlebag than a pack of chewing gum. In the shop. I’d recommend using a heat gun, but in an emergency situation, you can always flick your Bic, so long as you take the proper precautions.