Does a no fault accident on your motorbike affect your car insurance?

as a general rule, if it occurred on the road and the "motorbike" is being used as a "vehicle" as in driving on a roadway like cars etc vs offroad... then it very well may affect your auto policy. In some states a report is required for any death or injury which includes "offroad" but since in a case like that it was probably a "recreational type vehicle" it may not. The type and size may play a part as well. It may need to be classified as a "motor vehicle" to trigger the reporting requirement, which may be different deoending on the state.