Your bike is made up of different types of metals which you are aware of like steel and aluminum. But there is another metal that is found in various assemblies that is different and you need to be aware of what the differences are or you can make some costly mistakes. The metal in question is called die cast zinc metal aka white metal, pewter and pot metal. It is in the family of solders with several alloys which use a combination of zinc, tin, Bismuth, lead and antimony. These are soft almost plastic like metals that are used to cast carburetors, housing, covers at various points on your bike. They used to be popular with decorative housings on tanks or as master
cylinders and perches for clutches and brakes. They can bend if they are hit but at times they will snap off when you attempt to straighten them. On a simple item it is cheap to just replace them but on other parts like carbs they can be sometimes hard to find or expensive to replace, so why not just braze them.
Now thanks to a company called Muggy Weld http://muggyweld.com/... you can. This company makes a type of solder which melts at a temperature much lower than the material you are attempting to braze which reduces the risk of turning your $400 carb into a molten puddle of zinc. Because of the alloys that they use this solder with the correct flux can fuse with the old pot metal and effect a repair. You also don't have to worry about doing a tidy job (just don't be a slob) because you can always file or grind away and excess solder to make your repair look neat. The company also sells brazing rods for other metals like aluminum for making light duty repairs to your engine as well.
I recently had to do a repair to a Rochester Quadrajet carburetor which in certain years were prone to leaking from some plugs that were used in the casting process for the carburetors. Many mechanics simply fix this problem by using epoxy glue which does not last long as the gasoline can attack the glue. The only real fix is to drill out the plugs and drill and tap some screws with an appropriate glue with that requires tools and a bit more skill and it can still leak in the end. But not if you seal it with metal which is what I did.
You need to clean the metal before brazing. You can use a brass brush or a scotch brite pad. Good idea to wipe it down with acetone or alcohol to remove oil. The kit called Superalloy 1 for die cast zinc comes with several brazing rods and a small bottle of flux. Flux is a chemical typically boric acid which helps to minimize oxidation of the base metal and the filler rod. It also acts as a wetting agent to fascilate coalescence of the two metals. Without the flux the solder would just bead up and not want to fuse with the base metal. You basically apply the flux and heat with a propane or mapp gas torch. When the flux starts turning brown that is your que to start feeding the rod. Its a good idea to add a bit more that you need as you can shave off the excess easily later. Be careful not to over heat of the flux is turning black you have heated it to much.
The same type of metal can also be used to make castings from low temperature molds. You can sculpt out of clay, wax or 3 d print a pattern. Then make a mold out of plaster or silicone and you can melt this metal and pour it in. You can make custom ornaments for your bike, but that will be an article for the future.
The company has got some great videos on their site to give you detailed how to's. This is 3 clicks up from the Duck Dynasty repair using glue