Next: tires. Nothing is more important for safety and performance of your motorcycle than its tires. Look closely for cracks between tread blocks and on sidewalls. Also inspect for abnormal swelling, as air can leak through the carcass and separate the tread rubber from it, causing a bulge that will lead to vibration or result in dangerous tread separation. If you have a rubber valve stem, inspect it for abnormalities like cracks or swelling. Check your tire date codes, which are the last four digits of the DOT number on the tire’s sidewall. The first two digits are the week, the last two are the year. For example, 1618 would be the 16th week of 2018. If the tire is three to five years old, consider replacing it. If your bike uses tubes and you don’t know exactly how old they are, consider replacing them as well.