cam jetting.

[sickmojave]

I have an 03 400ex. it has a sparks advance key and has been rejetted to 152 main and a 40 pilot. well I just bought a XR cam and would like to know if I would need to rejet for this? and will it be ok the leave the sparks key in? Thanks Sick.

[cals400ex]

you will be fine with the key in. why did you go up two sizes on the mainjet? did you remove the lid, is it really cold, or do you have some mods done??? if your all stock with the lid in place, i would think a 150 would be good even with that cam, unless it is really cold. i wouldn't go bigger than a 152 on a stock bike even with that cam.

[sickmojave]

thank you for the help. the reason I went with a 152main was I did this Pipe Mod (http://home.earthlink.net/~gellett/exhaust/index.htm). seems to work for what I do. thanks sick

[cals400ex]

when i had my stock pipe, i did the pipe mod too. i also had the header weld grinded out and i had a modded air box lid. with these mods in the winter, a 152 was the jet. in the warmer months, i had to go down a size. good luck

I'd leave the jetting the way it is..:cool: