One-Up Moto Garage | Custom Motorcycles on Instagram: "More signs of too lean/rich: Too lean - idle will sound weak, may spit and sputter or misfire. Spark plug porcelain will look white like new. Too rich - idle will blubber and stumble, black smoke out of the exhaust is way too rich. Spark plug porcelain will be black. At idle the engine wants a ratio of around 12-13 parts air to 1 part fuel. So when in doubt you can use that to ration which way it needs to go depending on the symptoms. . .#mo