Now, when the up/down , presets, handlebar switches are pressed, the frequency is displayed for 5 seconds before the display reverts to the time.
The Only reason I can think that Clarion chose the original display with priority to frequency was one of safety.. IE, if the clock is displayed, you may be tempted to speed to get to your destination.
With that in mind and the fact that this mod involves you taking the radio out and opening it up, I have to issue the usual disclaimers.. You are solely responsible for any accidents, breakages etc as a direct or indirect result of this mod.
If you break your radio, you own both halves.. The mod works for me.
If you feel you would like this mod done to your Radio with the option to revert back, please Email me or PM me.
WARNING: This diode is GLASS. It WILL shatter if you lever it too roughly. Use a good 45W soldering iron and a good tip.
Here area couple of pictures for those who want to DIY this mod to their Radios.

For those with a Full service manual.. thats D514.. its the "Negative" end of the Diode thats lifted out of the Printed Circuit board..

The diode could be cut from the board but I recommend that it be desoldered..
If you attach a wire to the board and another to the lifted end of the diode, you can attach them to a switch to revert to normal operation.
This modification is "Read" by the processor at power on. So if you "revert" the mod, you have to turn the radio off , throw the toggle switch and power on.
Pete