Bonneville America Forums Forums Technical Forums Performance Mods double guess plug ?

Gray on the end of spark plug = lean ????
just one of those things I wish i wrote down.

Gray would be lean, black would be rich, tan would be good, but it's not really that simple... there are shades of- like sooty black or wet black, and really really gray, almost white and brown, dark brown, tan or light tan. Check the chart.
http://www.dansmc.com/spark_plugs/spark_plugs_catalog.html

Thanks jj great link. Im in there around a 20 or 21 I think I will enrich the mix. My partner was tring to tell me it should be gray. I always liked them with a powered tan color. I am going to bump up the main jet to a 130.