jetting

[cals400ex]

i am in the process of jetting a 400ex. i have a modified airbox lid and i drilled two 3/4inch holes in my exhaust or you can say gutted it. i am not running the spark arrestor. i got a new plug and took the bike out and started it and took off and had the bike floored in fifth for about 15 seconds. i turned it off and checked the plug. the plug was a light yellow color. i have never seen anything like this. i was running a 155 keihin jet. it is around 30 degrees F here. then i went out again but this time without a lid on and it seemed like the bike was a little quicker. i don't know why i got a plug reading like i did though. any suggestions???

[GoLikeHell]

Originally posted by cals400ex
i am in the process of jetting a 400ex. i have a modified airbox lid and i drilled two 3/4inch holes in my exhaust or you can say gutted it. i am not running the spark arrestor. i got a new plug and took the bike out and started it and took off and had the bike floored in fifth for about 15 seconds. i turned it off and checked the plug. the plug was a light yellow color. i have never seen anything like this. i was running a 155 keihin jet. it is around 30 degrees F here. then i went out again but this time without a lid on and it seemed like the bike was a little quicker. i don't know why i got a plug reading like i did though. any suggestions???

If the color looks wrong it could be a fuel additive. Try a different brand of fuel and see if the color changes. Sunonco 94 will leave a light rust color on your plugs.

Mark