"Go to the auto supply store and get yourself a pack of electrical wire connectors crimp type. Take one and run your throttle cable through it then back through leaving a loop at the end. Then crimp it down good. Now use a pair of plairs to flatten the loop.
Do exactly the same to the brake cable. inter coking the loops. It is very important that you mash the loop blat. That take the pressure off the crimp.
that should be light enough to return the carp throttle.
But take a look at the carp and see if you cant remove the throttle cable and install your brake cable directly to it. Sometimes you can and if so it is better to have one cable than to marry them