NGK CR9E. Advance Auto or Napa. Yes, right below the airbox. You may have to take the pair valve out (between the reeds) to get to cylinder 2 and 3 coils. It's no big deal, just pull it out without ripping the hoses. I can't remember if it HAS to come out because I replaced my plugs when I was doing the KLEEN mod (pair valve delete).I am looking for a place to order spark plugs online, anyone know a place?
Is the model # 3521?
Also is it easy to do the spark replacement? Is it right below the air box?