2002 mojave 250 motor ?

hi just got a 2002 with real low hours on it .i was wondering if there was a reason why when im in second gear and i rev it up it sound like there is something knockin in the top end like it needs the valves adjusted or is it just the sound of the motor? this thing is in mint shape it sat in a storage bay for 8 years it really has like 3 hours on it .everything is mint on it i got it for 1000 bucks.i think i got a deal .it was owned by some older guy that never rode it .thank god lol . so should i give it a 5 hour tune up like check anything or tightin something .thanks