well I guess you are talking about the so called "linkage arm" right ?
don't know about the KLR, but my LR4 has a pro-lever-system the "dogbones" work like the following, and may help you to clarify the game with the length.
now in spring time I fitted a riser kit to my LC4 Enduro the std. length is 127mm from aye to aye, for the pro-lever-system, the lowering kit for SuperMoto would be "longer" than Std., the riser linkage arms or "jack up kit" for long legs, tale guys and all Enduros has to be "shorter" to allow the rear fork to stay steeper which pushes the bike up, that's it
The differers is only a few millimetre, like 4-5mm either way for the "dogbones" to rise or lower the bike some 2-1/2 to 3cm. In my case it's grate makes a big diff....... better cornering ability as well........