While some states require bills of sale to be witnessed by a notary public, in Utah, two private parties can sign a valid bill of sale on their own. In general, a bill of sale is not a complicated legal document.
Transfer of a motor vehicle without a title may be easily accomplished with an Utah title bond. Utah defines a lost or defective title as "insufficient evidence of ownership". If the value of the motor vehicle exceeds one thousand dollars ($1,000.00) then a surety bond will likely be required.