well i dont know if a 7 is alright but i have a 2006 honda cr 250 and work for a honda dealership, right from brand new i dropped the heat range on my plug from a 9 to an 8, i thought about trying a 7 but im a bit sketchy about putting that hot of a plug in my bike an 8 work awsome with a pipe/silender/reeds and powerwing