How do you fix backfire on 1968 bug?

To fix backfire on a 1968 Volkswagen Beetle, start by checking the ignition timing; it should be set to the manufacturer's specifications. Next, inspect the spark plugs for wear or fouling and replace them if necessary. Ensure the fuel mixture is correct, as an overly rich mixture can cause backfiring; adjusting the carburetor may be needed. Finally, check for any vacuum leaks in hoses or intake manifolds, as these can also contribute to backfire issues.