If you are replacing the inner only and it broke at the top end, you should be able to pull the old inner out from the carb end.
Some throttle cables only come as a set, inner & outer, because they include 'lugs' connected at both ends of the inner and it can't be removed from the outer. When replacing the throttle inner only, I prefer cables w/ just the 'lug' for the handlebar end and I use a small removable pinch bolt at the carb end. If the outer is still in good shape, I can feed the prelubed* new inner down from the headset until it appears at the bottom end of the outer. Be sure you have a good tip on your new inner, still soldered tight w/ no sharp edges or loose strands and minimal kinks or 'corners' in the cable.
*grease or I like teflon spray UNLESS you have premium teflon lined outers - if so, don't add any lube.
PS Remove your headlite, speedo, throttle tube and any cable bracket inside the headset or you will be cursing the instructions above until you figure out that you need to remove all that stuff. With any luck, headset can stay in place...
⚠️ Last edited by V oodoo on UTC; edited 1 time