I was wondering if I need to replace my steering stem when I install 2+1 a-arms on my Raptor? If not what is the purpose of a longer stem?

 

Well I don't think it's necessary. Most buy them to motocross because of the anti vibe feature. Supposed to transmit less vibration through the bars with this stem. Also when they are longer that is usually due to most people changing bars to something like a CR Hi bend bar etc. etc. Instead of running the traditional bar with the crossbar in it. Hope this helps.