Has anyone adjusted the chain, besides me? Mine was too loose (and a little crooked) from the dealer, so it was one of the first things I had to do. Anyway, once adjusted properly, the chain should stay in specs a long time, since it's a good chain.
Here is how I adjust chains: Mark down on a piece of paper for both L and R how many lines show on the chain adjuster bracket...should be equal on both sides. When a chain is too loose, turning the adjusting nuts clockwise makes more lines show and tightens the chain. As an example, if there are 4 lines showing on each side before you start and the chain is too loose, when you are done, there should be about 4.5 lines showing on each side once the chain is back into specs. I have a block of wood with the proper chain tension measured off and it is easier to use that and place it near the end of the chain guide as per the directions in the manual vs. using a ruler.
Begin by loosening the axle nut a little while the bike is on the side stand. Next, place the bike on a swingarm stand and loosen the axle nut some more till it is quite loose, but you don't need to remove it completely. Now unscrew the chain adjusting nuts and set nuts on both sides. Say the chain needs to be a bit tighter. OK, then you will need to screw-in both adjusting nuts a little. It helps to mark where they were in relation to the swingarm before beginning with a sharpie so you don't get lost. How could you get lost? Cause when you start unscrewing the nuts, the wheel moves and it leaves a uneven gap on each side. OK, so now it is trial and error, but try screwing in both adjusting nuts a quarter turn. Don't try to measure anything now cause things will still change. Instead, place a thin screwdriver into the valley of the rear sprocket and wind the screwdriver up in the rear wheel a little until the chain becomes tight and there is resistence. This also forces the wheel into alignment and removes any slack a the back of the swingarm. Now your adjusting nuts should be against the swingarm on both sides. Screw down the set nuts, and tighten, but do not torque the axle nut. Remove the screwdriver and check the tension, straightness and that the same number of lines are visible on each side of the swing arm bracket. If so, put the bike down and torque it to specs.
What can go wrong? You can have the chain adjusted properly, but as you begin to tighten the axle nut, things go out of alignment and typically you will have more lines showing on the right than the left swing arm bracket because the wheel moved as you tightened the axle nut. You can remedy this by holding the rear wheel in place as you tighten the axle nut...OR what I do is NOT even touch the right side adjusting nut to begin with and only screw in the left adjusting nut a quarter turn. Now as you tighten the axle nut, the lines should match up on each side evenly and there will be a slight space (about a quarter turn) at the back of the right adjusting nut to tighten down along with the right set nut so in the end you screwed in each adjusting nut a quarter turn, the chain is even, and in specs.