As the title says, my '82 atc 200 fouls plugs constantly. I cleaned & adjusted the carb & it runs great, has lots of power & doesn't seem to smoke from the exhaust at all. But after a couple of hours of riding it dies & the plug is BLACK, not wet, but Black & stops sparking. I change the plug & away it goes. Any info/advice would be great. Thanks.
(Tried a hotter plug & it lasts a little longer, but the result is the same in the end)