If you have a vintage dirt bike, you might be forced to repair the existing cable, simply because there's nothing available to replace it. Or you might have to make one of those late night repairs so you can go riding or racing the next day.

It doesn't always pay to repair a broken cable. Usually by the time the cable has decided to break, the housing is kinked, or the shield material is worn through in 10 places. But like a lot of things, especially the night before, you sometimes don't have a choice.

Another thing that might demand an altered cable length, is the switch to a different type of lever, throttle, carb size clutch/brake arm. This can make a perfectly good cable to become too long or too short. Or maybe the cable you purchased at your local dealer is sort of, kind of, almost in the ballpark, but that's the only thing available at the time. There are universal cables that can be custom built to your own specs. But you can also modify the one you have. At least most of the time.

You can repair a broken cable if you have all the parts and it is not frayed down inside the housing. I have seen, in desperate situations, an entire cable ball end formed from solder!

For the repair, you will also need a soldering iron, or gun, or a butane torch: some very sharp side cutters and some acid core solder. Repeat. Acid core solder, If you repair your cable with resin core solder, it will probably break during cable installation.

Depending on how much adjustment you had, or didn't have, on the lever, you will want to shorten the housing to compensate for the loss of the end of the
cable. If, for instance, the cable broke one inch from the end, the housing should be shortened one inch.

Also keep in mind, that whatever you remove while repairing the cable, such as springs, barrel adjusters or anything else between housing and the end of the cable, should be reinstalled before soldering the end back in place.

If you have a cable that you're trying to install to a different set of levers, and the free length is not enough to reach the lever, then the housing can be shortened.
If you aren't comfortable with removing the cable end, secure the housing in a vise, remove the housing end (heat does the job best)and with a pair of sharp side cutters, pull the cables housing out like a spring.

If you simply try to hold the housing in your hand while you pull the winding off, it'll stretch the housing and make it very spongey and virtually unusable.

While this may be the quick and dirty method of shortening the housing, it is much more sanitary to remove the cable ends, slide the cable back inside the housing, and cut the housing off at the correct spot.

The replaced cable end will be as good as a new one if you make sure that the solder has good penetration and you don't cook it to death with the torch.

You don't have to toss this dead cable in the trash can. You can fix it as a spare, or just to get you going the night before an event.
Secure the broken piece in a vise and heat with a soldering gun.
Using the vise as a leverage point, pull the tip off while it's still hot.
For a basic repair, cut off the housing the same length as the broken piece.
Remove the end cap from the piece of housing. Try not to bend or deform it and use a little heat to ease it off.
Put the cap on the cut/shortened housing and heat it up a bit.
When hot enough, simply push the cap down on to the housing.
Replace the cable end, making sure everything that came off (springs, spacers, etc.) go back on at this point.
Using side cutters, flare out the end of the cable, then slide the tip up flush with the cable end.
Heat the tip first, then apply acid core solder. Penetration is fine when you see solder "sweat" out of the bottom of the tip. Wipe any excess off the cable.
Once it's cool, the tip should be as good as the original.
If only the housing needs to be shortened (for increased free length), secure the cable housing in a vise at the cut-off point	.
Strip the housing shield (cover) with a razor blade to the cut-off point.
Using side cutters, pull the coiled housing out like a spring.
Gently unravel - unwind - the cable housing from the cable.
Snip off the excess and don't nick the cable in the process.
Trim back the housing, then heat the cap and press it on.
There you have it: a longer free-length cable.