To jet or not to jet!!!

[nosfed98z]

I have been riding my 300 in the river the last few times I have went out. My air box did not have a lid on it and it was jetted that way. The question that j have is I put a new airbox with a lid on, how do I know if I need to rejet the carb. Thanks for the help.

[m0t0xk1d]

run it around full throttle for a little while and then let it cool down a little. after it cooled down take out the plug and look at it. if it a light brownish tan then its perfect and no need to rejet. if it black or has some gas on it then you need to jet down. if its its white then its to lean and well you wont run into be lean with this. if its black(too rich) then you need to jet down and re do this until it a nice light brown