I don't condone cheating but sometimes your friends cheat and the only way to take gold in an event is to either race in Guest mode or also cheat.

The goal of Speed Record is to beat the top speed in one complete lap.  That top speed can be obtained on the grass, by backing up at the starting line to make the fist straight away longer, or even running a section of the track in the wrong direction.

For example, to hit the top speed on the Suzuka track, turn around at the starting line (going the wrong direction) and go to the very beginning of the straight away.  Turn around again and use the full length of the long straight to hit your top speed.  Make sure your brakes are turned off so that can continue to gain speed after the end of the long straight.

FM really ought to apply the same rules to Speed Record events that they have to Time Trials.