Hi Craig,
Sorry only just read your post, you should have titled it "Shogun tyre pressure"
The answer is a small decal on the drivers door pillar and it is 2 bar for everything except sustained high speed. This is also repeated in the handbook.
2 bar is 29 psi
I leave mine at 29 psi all the time with no problem - the older mk11 shogun was happier at higher pressure and I concur with Marks figure.
If you overinflate you will wear the centre of the trye prematurely with no actual stability advantage.