$6,900 seems a little high for a two-year-old CFM ATV. New 800XCs are only $8,499. KBB has the 2017 CF800s at $6,435 so..$6,200 or so would be fair...unless- check that it has the upgraded air filter. If not, offer 4,500 or walk away because if it's had the OE paper filter in it for 800 miles, the chances it is at the end of the top-end's life expectancy is high.