Instructions
Load "Diddy Kong Racing" and enter the lobby. Drive up to TT, the small clock character, and honk your horn to grab his attention.
Choose "Time Trial" from the options TT will give you.
Move the analog stick right or left to change the option from "Time Trial" to "Normal Race." This will allow you to race on the course without a ghost.
Delete ghost files from your Nintendo 64 memory card by entering the "Save Options" at the main menu, select the ghost files you want to delete and press "A" to confirm.