I just installed new spark plugs on the S2K. Here are my old sparks plugs. I know #4 spark plug has some carbon build up (running rich?). #1 #2 and #3 looks to be ok.

What are your thoughts on this and if #4 is running rich, what do I need to do.

 

IMO, those plugs look good. A little carbon isn't uncommon on an S2000, especially if you hit VTEC occasionally. The electrodes don't look worn, and the insulators around the electrodes aren't fouled.

 

Thanks Slalom for the second opinion. Much appreciated. I had a few buddies take a look at them as well and they said the same thing. Good to know. I could probably use them again. The gaps were still within their range limit.