There was a product available at one time thru T Rex Tommy , that if you wanted to go backwards the quad could be turned off . flip a switch, restart it and the quad would go backwards.
Other wise your facing the wrong way when you sit on it.
Pierre Karsmakers had his Factory Works Yamaha do this at the starting line in the 1970's, they claimed timing was the problem.
I figured Jimmy Wienert had something to do with it.