Thruxton 24 Hr Clock??

Can't answer your question mate, what does it say in the owners manual?

 

You could try this:

"To set the clock, turn the ignition to the ON
position. Press and release the reset button
until the clock is visible in the display screen.

Press and hold the reset button for
4 seconds. After 4 seconds either 24 Hr or
12 Hr will be shown flashing. Press and
release the reset button to select the desired
clock display. When the correct display is
shown, do not touch the reset button until
the clock is shown with the hour display
flashing."

Might not work, but worth a try?

 

Mmm... Pity...