Re: throttle cable
1st, if you have the grubee type throttle grip, see if there is a barrel adjuster near the hand grip. (a shiny metal nut and threaded barrel, maybe near a bent steel cable guide. If you have one, you should be able to adjust it some there to get more cable length.
If not, you can do like Al, but you will have to pull the inner cable through, at least a few inches so you can cut the cable housing (preferably with standard bicycle cable cutters). Be sure to account for the barrel adjuster on the carb, and the one near the hand grip if you have one, before calculating how much housing to cut off. Else you will have to start over.
If you can solder an end like Al did, just go to a bike shop, get a v-brake noodle, a gripshift cable and housing. You can make your own cable to any length you want, and the noodle (bent cable guide) will either sit in the end where housing goes into carb, or at the end with the grip, and make a nice smooth bend, helping you de-clutter your cable routing.
1" roller Dax Friction Drive and Tanaka 3300 with mods.