1. Loosen the axle nut. The axle nut is located on the right side of the rear axle. Use a wrench to loosen the nut, but do not remove it completely.
2. Loosen the chain adjusters. The chain adjusters are located on both sides of the swingarm. Use a wrench to loosen the nuts on the chain adjusters.
3. Adjust the chain. Use your hands to move the chain forward or backward until it is properly tensioned. The chain should be tight enough so that it does not sag, but not so tight that it is difficult to move.
4. Tighten the chain adjusters. Once the chain is properly tensioned, tighten the nuts on the chain adjusters.
5. Tighten the axle nut. Tighten the axle nut until it is snug.
Here are some additional tips for adjusting the chain on your 1999 Honda TRX300EX:
* Make sure that the chain is clean and free of dirt and debris.
* If the chain is too loose, it can slip off the sprockets and cause damage.
* If the chain is too tight, it can put unnecessary strain on the engine and transmission.
* It is a good idea to check the chain tension regularly and adjust it as needed.
