How do you tighten a chain on a 125cc ATV?

To tighten the chain on a 125cc ATV, first, lift the rear of the ATV and secure it on a stand. Locate the rear axle adjustment bolts on both sides of the swingarm, and loosen the axle nut slightly. Turn the adjustment bolts evenly on both sides to pull the rear axle backward, increasing the tension on the chain. Once the desired tension is achieved, re-tighten the axle nut and double-check the chain slack to ensure it is within the recommended range.