orange spark from my 1985 fz400

[nestor123]

Hello, got.myself a fz400 1985, I've just fitted a new battery bad serviced the carbs it runs but its hard to get going, I've had the spark plugs of to test the spark and I've got spark but they're yellow, I know this is a sign of low voltage buy how can this be? It's a New battery? The plugs have been fowled a few times in the past, could these cause the orange spark? Also what's the correct gap?

[nestor123]

Just pulled plugs out found one to be not sparking, I assume the constant fouling before the carb setup had knackered it, I've replaced it and cleaned the other's up and it fired up with slight hesitation, its warm now but I'm guna let it cool down and try it again....
I'll update shortly