I've never had much success keeping any paint on the center exhaust ports. I've tried the Hirch stuff. Didn't seem any better that the local stuff. I've tried light dusting a couple of coats. Doesn't seem to make much of a difference as far as my motor goes. I've given up trying. The dupicolor stuff is as good as any other you can find. At $4 a can you can afford to hit it before every show.