The manual wants you to replace the plugs every 7,500 miles. I checked them out last week with 12.3k and it looks good. It has an iridium tip if I'm not blind. I think the manual is over exaggerating on the change intervals. I was looking at my friend's 1000RR's manual, and the plugs are not recommended to be replaced until 32k. Can someone explain why? I think Kawasaki is big on generic manuals. Just like on my old ZX7R the manual calls for regular octane but under the seat the sticker calls for premium.WTF Kawasaki?