Honda 400EX with a "white" spark plug tip

[mongo]

Here is my problem. I am getting a very white tip on my spark plug. What can cause this? I read where it is "lean" or " running hot". Anyone got a suggestion that I can try? I don't want to go turning screws or anything unless I know what the problem is (or isn't).

Mongo

[450r91]

Sounds like your running a little lean! You can either mess the with fuel/air fixture screw or go up a few sizes on your main jet! Also how did you determine that it is white( Run it hard and then shut it off or letting it idle?)