Re: Shortening clutch and throttle cables
I changed from flat mountain bike bars to upright BMX style bars this year so I had to completely re-cable my bike, it worked out really great for me...
First of all, you need to make a nice clean cut on the cable housing without pinching or crimping it, otherwise it will wear the inner cable. This can be kinda hard to do with regular side cutters, I purchased a Park cable cutting tool that does a nice job, it has rounded jaws that are designed to cut cable housings cleanly. I use the same tool to cut the inner cable, it does it well without fraying.
As for the ball end on the carb cables, I just made a new ball end in the position for the shorter cable and then cut off the original ball end. Making a new ball end (for the carb side) is easy, just take some thin solid wire (like telephone wire) and wrap the (bare) wire around the cable a few times where you want the ball end to be located, then take a soldering iron and solder the wire in place on the cable leaving a ball of solder about the size of the original ball end. You can size the ball end either with heat or you can use hand tools to cut/file it into proper shape.