Do you mean which socket sizes? Get the sizes of the wrenches you have in the original tool kit: 8, 10, 12, 14mm. But it will be cheaper to buy a full set. 1/4” drive sets usually span from 6-14mm or so. 3/8” drive sets usually go from 9-19mm. Get a 1/4”-3/8” adaptor and a 3” and 6” extension (also frequently included in a ratchet/socket set).
Note: Japanese vehicles tend to use 8, 10, 12, 14, 17, 19mm heads, whereas German and American vehicles tend to use 8, 9, 10, 13, 15, 17, 19mm heads. 11mm is used in brake line flare nuts, and 16 and 18 are oddballs (e.g., bicycle cranks and GM brake calipers). I don’t think there are any 13 or 15mm heads on the KLR, but because they are common on other bikes, I recommend you include the 13 and 15 sizes in your kit. Ya never know when you might want to help out a guy with a KTM or BMW!