Dirt Rider Magazine

i am going to buy a 450 motocrosser and with the price tag that they come with i want to buy the right one. i want a bike that is going to last and is going to be reliable also i am also very tall and like the adjustability of the new kawi
i am not a motocrosser but more of a woods rider but jump my bike every chance i get. i am riding a ktm xc300 right now but dont like the suspension period. and the price of dumondtech is rediculous.so i am switching up any advice is welcomed
what is the average life span of a kawi engine if it is maintaned and not motocrossed?