2002 CBR 954 has a small hole underneath the exhaust. I've heard they are for draining the spark plug holes and also to let air in for emissions. Just searching for verification as I can find no official documentation in the repair or owners manual. Here's what I can tell you is that I am going on vacation for a week and decided to fill the cylinder's up with marvel mystery oil to let them soak around the rings and marvels oil leaked out of these holes. If they are for the exhaust to let air in, would that not constitute an exhaust leak? Does anyone have a cut-away image of the head to shw exactly where the hole comes out in the head?

 

they look like spark plug drain holes. i would spray some degreaser there and see whether it comes out of the spark plug well. if it does then it's a spark plug drain hole. usually you can see a small hole/passage at the bottom of spark plug wells.

 

You are correct. After I got my flashlight out and poked and prodded I can see where the holes come out in the spark plug area. Thanks for confirming my suspicions as i had never seen any engine with them before.

 

@wickedly clever fantasy you are welcome