The most important things cant be determined until its in your garage but here's a place to start.
How clean is it? A clean bike usually indicates the owner took pride in taking care of, hopefully on the inside too.
Obviously crash damage, look for damaged steering stops or chips in the frame caused by the clip-ons crashing into the frame up near the headstock, bent rear set tabs, scuffed fork legs, axels or swing arm.
Expanding tank, check the clearance between the tank and damper rod mount, should have some clearance and not touching. Not much you can do about it but if its been replaced under warranty with a new tank that would be a plus.
Starter sprang clutches are known problem, if the starter spins while trying to start it suspect it may need replacement - not cheap. If the engine cranks really slow it probably needs a new battery.
1X98 have a known issue where the air filter seals poorly on the ends, tough to check but if the interior of air box really dirty suspect the engine has ingested a fair amount of dirt and grim this could lead to worn piston rings and cylinder walls. Check for blue exhaust smoke or conduct a compression check.
Drop a 1/2 quart of oil from the engine after its warmed a little, if its really black this may indicate poor maintenance schedule, also look for bits in the oil pan. For the benefit of the owner replace it with a good premium synthetic.
IMO a dealer sold bike is no better than buying one off a personal seller. The 1198 is newer engine design and has traction control. I currently have a 10' 1198s with short style Termi's slip-ons, it sounds much better than the older longer version - looks better too.
