hello all, 05 electra glide classic with 88ci, screamin eagle stage one kit and Rineheart exhaust.

The other day I took out the plugs out which are screamin eagle performance spark plugs as here in ontario as its cold season to ride and usually park the bike this time of year till spring. I removed the plugs to find that (front plug) was carboned over with a grey colored carbon and miraculously still able to fire. The rear plug was perfect color and not carboned at all.

Can anyone tell me what might cause the front plug to carbon over like that? I always put top grade fuel in the bike which around here is sunoco 94 octane.

Thanks in advance for any replies.

 

THIS might help