Welcome! I'm glad to hear we have another xf250 owner around. I have a 2013 xf250 and there are a few other owners on here occasionally. I have 18,000 miles on mine mainly commuting and fire roads and I have really enjoyed it. There is a lot of info on this bike spread out on this forum so you came to the right place. The engine, trans, and some electrical components are shared with the tu250x which is a good thing. The rest of this bike is something else, I read somewhere once that a semi legit UK motorcycle company designed it.
There are a few places to find replacement and performance parts and they are cheap. If you haven't used one of the Taobao sites (I use Engtaobao.com) then you should get familiar with them as their parts are the cheapest; I have a box of spares in my garage I paid less than $50 for.
For tires the most sensible choices imo are the Kenda 244 or Shinko 700. If you need a more heavy duty nobbie you may want to order a 21" front wheel on Taobao.
Most recently we have been sharing info on a general xf250 thread you can see here, it covers a lot of stuff but most recently one of our members picked up and exhaust kit from Lextec which makes a lot of parts for this bike. Some of their stuff is available on Amazon and some you have to order directly from the UK.
http://chinariders.net/showthread.ph...ighlight=xf250
Here is a recent one where I covered all the parts resources for this bike.
http://chinariders.net/showthread.ph...ighlight=xf250