Kind of a lengthy explanation. The adjustment is made at the box where the wheel is.
Under the box is a nut. Loosen it and the box will come off. It has one small phillips
screw in it holding on a cover plate. Remove it. You can see where the cable hooks on.
The housing on your cable has a bunch of straight wires in it. Cutting it shorter requires a
special cutter...or pull the housing off and cut it with a hammer and sharp chisel. Well that
is what I use. Put the small end back on the housing. Measure how much cable is sticking out before
you cut it and then make sure it has the same amount sticking out when your done. Then just
reinstall the cable under the nut in the box. To adjust put the shifter in second and adjust where the little
yellow dot is between the two lines. Hope this helps. Do not tighten the nut under the box hard. You will
strip it out. Its doesn't take much to hold it on to the axle. Its just plastic or aluminum....go easy.