I have the 150 and i think it is faster than most or all 85s i raced my friends souped up yz 85 and was winning until i got scared ( still not used to bike only had it for 3 or 4 days when i raced him ) but i was winning then he raced my other friend he was on my bike and other friend was on the yz and my bike won so what is faster My bike is completely stock and the yz has everything aftermarket except the actual engine Also is it true that the 150 is not allowed in the 85 class no more because that is what ive read and it said because the 150s were tearing the 85s up. Also why do people talk so much smack about 4 strokes i really like them because its alot less maitnence whoever says two strokes are less maitnece is dumb because 1. You have to mix oil with gas 2. Your always changing oil 3. The engines always need a rebuild. With a four stroke you just need to put gas and change the oil once in a while