What would be the correct way of removing the tarnish off a motorcycle engine and what would I use to polish to almost a new look?

To remove tarnish from a motorcycle engine, use a mixture of baking soda and water or a dedicated aluminum cleaner, applying it with a soft cloth or sponge. After cleaning, rinse thoroughly with water and dry completely. For polishing, aluminum polish or a metal polish specifically designed for engines can be used, applied with a microfiber cloth or polishing pad to achieve a near-new shine. Always follow up with a protective coating, like wax or sealant, to maintain the polished finish.