Bike is a 1997 Sportsman with a 2006 750CC engine. The transmission is the 650 kickstart 4 speed. The rear end is a selectable 2 wheel drive (not the Sportsman full time 2 wheel drive unit). so I have a Frankenbike.
Bike has passed by 5 previous owners in its 11,000 kilometer history. All dealers are "longtime out" of the equation.
The petcock is the original sportsman petcock with Run=Down, Reserve=Up, Off=Left or Right. I'm assuming the vacuum actuated petcock on the newer bikes was a "fix" for the leaky keihin carbs?? That way you won't burn your garage down on an overnight fuel spill.
Your '07 Patrol probably has a nice clean tank that is being kept dry and full of clean fuel. Mine is not bad but the extra screen won't hurt anything.
Sort of like "can't be too rich, too thin or too good looking". Fuel can't be too clean as long as filter flow rate matches consumption rate.