Speedo problem help!
 

Picked up my bike last week....riding last night i felt like i was going faster than the speedo was telling me....had a friend tell me that on these 2007 1k i should be reading 80 mph in 6th gear at 5k RPM......well im reading 59 or 58....Stock sprocket on back.....haven't checked front but even if front isn't stock teeth...its not going to throw the dash off by 20 mph....any help is appreciated...