What year is your KLR and how many miles are on it?
The balancer chain is good for well over 100,000 miles. It should be replaced when the 20 link/21 pin length reaches 193.4 mm: New 20 link length is 190.5mm
It is the wear on the rubber bumpers on the sides of the sprockets that causes most of the slack not chain wear. If the rubber is torn up, you may have to replace some of the sprockets.
On mine I just re-indexed the chain by one tooth on all of the sprockets including the crankshaft sprocket without moving the sprockets. So, the timing for all the sprockets was unchanged, but the chain links were sitting on new (not depressed) rubber. The outer links were sitting on non depresses rubber next to where the inner links were before and the same for the inner links. I picked up half an inch of doohickey rotation by doing this.