gentlemanjim
More Wrenchin than Ridin
How black is black? A pic will help. Do they foul and not fire? Too rich is better than too lean. My left plug looks a bit sooty and the right looks nice and tan. Bike runs awesome. No decel popping, crisp throttle response. So I don't look a the sooty plug and don't care. Mixture screws won't alter the jetting other than at idle. You might closing them down until the idle starts to drop and surge then back them out until you get a smooth idle. Let us now if that helps.