03'400exrider
04-25-2009, 05:49 PM
HEP!!!!
I rebuilt my 400ex... I put a 440 big bore kit it it. Stock Main jet was a 148. After the rebuilt, the plug turned white, so obvisouly much lean. I put a 165 main and same thing-- white. I then put a 185 in and now it falls on its face..like it is too rich. However, the middle of the spark plug is white and the outer is very black....what does this mean?
basically, I need to know what i means if the inner part of the spark plug is white and the outer very black.
Thanks!
I rebuilt my 400ex... I put a 440 big bore kit it it. Stock Main jet was a 148. After the rebuilt, the plug turned white, so obvisouly much lean. I put a 165 main and same thing-- white. I then put a 185 in and now it falls on its face..like it is too rich. However, the middle of the spark plug is white and the outer is very black....what does this mean?
basically, I need to know what i means if the inner part of the spark plug is white and the outer very black.
Thanks!