I OWN a 2013 XT250. I bought mine used two years ago, and have put about 1000 miles on it since.
The fuel injection is great. Starts right up, no more carb problems. Its single cylinder, two valve engine that makes about 16HP, so its no power house. BUT, its reliable, and gets 75 mpg. The previous model the XT225 had a 6 speed transmission, and its unfortunate that the newer XT250 went back to the 5 speed transmission.
Top speed I have ever had it was 73 indicated which was actually about 65 mph via GPS. The speedometer is optimistic about 4-8 mph, so I use the speed on my GPS to know that actual speed Im going.
The bike is not happy at top speed, although they will supposedly run at top speed all day long. The bike is really happy in the 35-55 mph range. Its a cool around town bike, and cool for what it is.
Its not all that great off road, so dont consider it a fantastic dirt bike. Consider it more of a light trail bike or street bike.
If its all stock, definetly drop a new battery in it. Shake out the air filter (probably in good condition at that low of mileage), and change the oil. It needs a valve adjustment at 600 miles, so ask the owner if that was done. Most people dont.
On the oil change, most filters dont come with the o- rings for the oil filter housing, but the Fram CH6097 does. You don't have to change the o-rings every time, but its nice to know that you can just buy the Fram and it comes with o-rings, which would cost $10ish dollars by themselves at the dealer.
The factory battery was getting weak in mine, I replaced it with a on sale $42 at the time ACDelco. Its been a good strong battery, especially for the price.
https://www.amazon.com/ACDelco-ATZ7SBS-Specialty-Powersports-Battery/dp/B00BFLVUDO/ref=sr_1_3?s=automotive&ie=UTF8&qid=1530930846&vehicle=2013-1210-20592-20-----13957------2-0&sr=1-3&ymm=2013%3Ayamaha%3Axt250