Please help what dirtbike should i get with good performance?

two stroke bikes work best when they are hot,, as long as the oil is the correct ratio. i would go for a honda crf110 (i think it is) its four stroke maybe abit more expensive but Alto easyer to ride on track than a 2 stroke. If u want a two stroke get a Z 85, they are easy to ride, parts are easy to buy on ebay ect, lots of people have them so theres always some 1 to help!