You need to check your spark plug and see what color it is.
Black plug means you're running rich, tan / brown means it's jetting properly, white means it's lean.
Blue smoke when you hit throttle hard does not mean you're running rich, more than likely oil smoke.

 

thanks a lot!

 

Will it give me more top end if I take one out in the front only?

 

No, you add a tooth on the front sprocket to get more speed. You will lose some low end torque and gain some speed.

 

thanks! ya...teh kind of riding i do is not much low end stuff so good!