Fit the new cable with the adjuster screwed as far back as it will go.
Pull the inner through and cut the drum off just past the end of the lever
Fit a new drum
Most motorcycle shop will have an assortment of them .
You tube is full of instructions on how to solder a cable end on.
I have a bird cage punch so when I come across a case like this I cut the cable end off & fit a clamp on drum ( also availible from motorcycle shop ) then move the clamp on fitting up the wire till the cable works as intended , then I cut the cable a fit floating drum in that position.
FWIW when you pull on a cable, the cable tries to twist because of the lay ( twist ) in the strands )
This twisting action is supposes to be accomodated by fitting a ball end to one end of the cable.
In practice this does not work and the regular twisting of the cable causes it to fail due to fatigue near where the drum ( or ball ) end is soldered on.
Putting a free rotating drum on the drum end means that the cable can rotate at both ends and usually will now last forever .
I have motorcycles that I made cables for over 50 years ago and they are still working fine .
Some Lanolin based cable lube or dry teflon lube ( pushbike shop ) will prevent rust and keep it going forever .
Never ever use WD 40 on cables.
