Which of the following is illegal while operating a motorcycle in Indiana?

Operating a motorcycle in Indiana requires that the rider possesses a valid motorcycle endorsement. This endorsement ensures that the rider has completed the necessary training and understands the rules of the road specifically applicable to motorcycle operation. Riding without this endorsement is illegal, as it not only violates state laws but also puts the rider and others on the road at risk due to a lack of demonstrated riding competency.

In Indiana, additional factors such as riding with a passenger, riding after dark, and riding in the rain are not inherently illegal, provided that the operator adheres to safety regulations and operates their motorcycle within the law. Therefore, the necessity of having a valid motorcycle endorsement is crucial for lawful operation.