Oil level: Fill it up close to the maximum but not over the maximu or you will create a holdup. Too little oil however could cause jiggering of the oil pump, especially in steep turn or when wheeling.
Water level: A proper water level is necessary not to overheat the engine. Water temperatur should not pass 110°C (general rule, specific manufacturer indications to be taken into consideration).
Brakes: Holders, conditions of the brake discs, as well as brake levers to be checked.
Chain: Regarding the wear of the chain you have to base any judgment on driven km. A visual check is rather difficult. Concerning the tension of the chain the bending should be 3cm, rider on the bike.
Screws: Check the screws of the main components like wheels, brakes, as well as all screws and lids of the liquids (oil, cooling, brakes).
Body: Make sure its tightened properly (if you have one), its clean and in proper condition (no broken edges, no cracks). Lenker Befestigung????. Flood lights, direction indicators, rear mirrors are allowed but lead to costly replacements in case of a crash.
Exhaust: Condition, fixation and authorization need to be checked. Because of increasing noise emissions genuine exhausts are the preferred ones. In case it has been modified make sure you've got the proper approvals. Check back with the organizer in case of doubts.