I have a raster in ArcMap (built using sum function in cell statistics), and only want to show the water parts of it (band 128). In doing so I only need to show multiples of 128, however there are over 40 bands which are multiples of 128. I have done 1 of these rasters (but I have 15 more I need to do), however I am wondering if there is a way to save the band value and also the symbology so that I do not need to spend so much time going through each one and deleting the unnecessary bands (of which there are thousands of).
I´m not sure what you mean by deleting the unessecary bands. Do you reclassify it, or just symbology?
For symbology are many ways:
You can safe your symbology the same way as for vectors by saving it as a layer-file (.lyr). Or you can use the import option directly in your project. When you are in the symbology tab of your next raster you have in the top right the option to import the symbology from the already done layer (the folder symbol).
Even easier is to put them into a raster-catalog. You can create one into a file geodatabase and load your rasters into it (all just some straight forward right-click actions). Then you can change the options for all rasters at once if the catalog does not build it already for you, because it takes the symbology from the first inserted file.