2021 KX250: Installing a New Chain and Sprockets 

Here's the complete procedure for installing an X-ring or O-ring chain and front and rear sprockets on a 2021 KX250. This procedure will be very similar on most modern dirt bikes.
Note: The chain used in this video comes pre-waxed. If your new chain does not come pre-lubed, remember to use the recommended lubricant or wax. Also, some of the steps provided in this video can be done in a different order. This is the order that works best for me based on the tools I'm using and the fact that I'm doing the project all by myself.