If you need to separate out a bunch of elements and/or don't want to disturb the placement of the elements on the drawing, I recommend the following procedure (Windows/Linux shortcuts included to help speed your workflow):
Open the Layers dialog (ctrl-shift-L)
Create a new layer called "New"
Create a new layer called "Working Space"
Create a new layer ...
I assume you are seeing something like this, followed by a lot of code:
I would look at the number of anchor points you have in the SVG file. More anchors points can typically increase the file size as there is more information to be rendered.
I opened the two SVG files in Illustrator and screen shot them in outline mode. (It's easier to see the actual paths this way)
This one has 156 anchors points
This one has 686 anchors ...
SVG files use uncompressed, human-readable text to describe an image so that it can be recreated with a render engine, such as the one included in your browser.
PNG files use compressed binary data to store exact binary information.
Human-readable text will always have some size overhead compared to vague binary dataflags that only need to be a few bytes (...
The SVG file is bigger because it contains more data (in the form of paths and nodes) in comparison to the data contained in the PNG.
SVGs aren't really comparable to PNG images. One is vector, the other is raster, and never the twain shall meet! It's as if you are making an assumption that SVGs should be as small as a PNG, and that isn't always the case. ...
One solution that I've discovered is to
1) Convert the object to path Path>Object to Path
2) Select all paths, including the former object
3) Use a lasso to select all of the desired nodes (i.e. all of the former object and the end points of the paths)
4) Use the arrow keys to reposition the nodes