I don't know how good a mechanic you are. So better take trustable mechanic for selecting the bike. Try OLX or pakwheels. Last resort should be bike mandi. If you are living in a city. Its hard to find both good bike n good mechanic.
If in a small town. Easy to find.
Also keep asking for the chinese bikes reviews and qualities. There will be some posts here on Pakwheels i am sure. Good luck. Jo bhi lein Allah barkat day.