Right, I have a definitive answer from a tech chap at Yamaha UK...

He doesn't recommend using any of the block connectors to hook up your GPS power cable - the four pin block terminal under the seat is for the (optional) alarm and connects to the immobiliser circuit - and although I've found it offers switched power, he couldn't guarentee it would work properly or not booger something else up...

So, if you want the GPS swtiched on/off with the ignition, since there are no dedicated switched terminals available, he suggests taking a live feed from the brake light circuit (this is easy to access under the seat) on the loom side, and earth direct to the battery.

Sounds fair enough to me... back to the garage I go (again!)

xxx

(ps. Obviously if you want a permanent live feed, you can simply take it directly from the battery, or the Optimate connector on the left side frame rail).

__________________
"Where we're going, we don't need roads..."

JennyDakar.com