Austin97

Replacing the chain as maintenance? Absolutely not. If your chain is rattling or something it's the tensioners, they do go bad occasionally, I would replace the chains and guides and sprockets at the same time as tensioners, but by no means would I replace any of it without having a problem. It's not like a belt, the chains don't stretch over time. The tensioners take up enough distance to make up for the tiny bit of stretch they get over time.

Big. D

Allows the piston to travel further up and get more compression.