Civil RICO Amendments Act of 1986 - Provides that civil claims arising from violations of the Racketeer Influenced and Corrupt Organizations Statute (RICO) shall be subject to settlement by arbitration. Amends RICO to modify the definitional section. Includes a separate definition for "fraudulent activity." (Such activities were previously included within the definition of "racketeering activity.") Amends RICO with regard to injunctive relief and the recovery of attorney fees in civil actions. Provides that damages in such actions shall not include payments for pain and suffering. Allows the court to require any party filing an improper or frivolous pleading, motion, or paper to pay certain costs, including attorney fees. Allows the Attorney General to bring a civil action on behalf of the United States where the United States is injured as a result of a violation of RICO. Allows any State attorney general to bring a civil action as parens patriae on behalf of any individuals residing in such State who are injured as a result of a RICO violation. Allows recovery for three times the actual damages in such actions. Provides a four-year statute of limitations in such actions.