I'm assuming you mean the Enduro...
If so, the thing that is most likely to fail are the forks - the coating goes on the legs, leading to the seals failing. To check them, you need to get the front end of the ground and look for any play in the legs. While you're there - this is a good time to check the headstock bearings too.
Being a 12 based bike, the final drive can also be prone to failure so check that for play.
It's a big bike, with a powerful engine so if it's got lots of miles and has been used a lot off road, then the clutch could be worn too...
But the HP is a tremendous and addictive bike - if you love it like so many others do, you find the money to take of these things
Out of interest, what kind of thing are you looking to use the HP for?