Yeah just about any soldering iron, barring the really small ones, should suffice for working on a bike. Go ahead and buy a cheepie from Radio Hut, just don't go in for the smallest wattage. Unless you're going to do a lot of soldering, or are going to do precision work such as soldering printed circuits, any run-of-the-mill soldering iron of any quality at all should do it for you. Personally I have several soldering irons for different applications, but I save the nice ones for when I really need them.
mystic_1