Jetting (Again)

[FoxMxRiders]

My 400ex is now STOCK but I put a dynojet kit in for the jetting of the futur mods.I follow the dynojet instruction sheet.Im below 3000 feet then here my current jetting

Mixture screw 3.5 turn on the stock pilot jet
Dynojet Needle at third groove (center of the needle if ma memory is good)
Main jet Dj142

My 400ex run good,no popping,no backfire,no hesitation when I rev it ... run good

So I went riding and when I came home,I check my sparkplug color and the color of it was Dark Gray.

Im correct with my jetting??Or im too lean?

Another question,with my Wb R4 slip-on,Uni filter and open box what main jet will be good?

[FoxMxRiders]

ttt

[FoxMxRiders]

Someone can help me plz?

[400exhauck]

are you running a stock air filter and is the lid on or off? also what kind of exhaust do you have? i have a stock exhaust, a K&N filter, and no lid, and dynojet reccomends a 165 main jet... it all depends on your setup... i havent checked my spark plug yet, but the bike runs great...

[FoxMxRiders]

Im stock for now ... stock air filter,stock exhaust and lid is on

my bike run great but just the sparkplug color that I don't understand

[cals400ex]

i say your fine.

[FoxMxRiders]

I think that too cuz my bike run great but its just my sparkplug color that im confuse with it

[2004exrider]

dark grey to light brown is exacly were you want to be when its white thats when its lean

[FoxProRacing]

Thanks :)

[DH400EX]

i have the same problem. I have a Pro Circuit slip on, UNI air filter, wit the air box lid on. I put a 160 Kehin main jet, and 2.5 turns out of the mix. screw, but when i would let off the throttle and shift down, it would start spittin and sputterin, so today i turned the mix screw aronther ½ a turn to make it 3 turns, and it was still sputterin a lil, i checked my spark plug and it was dark grey. Should i turn the mix srew another half a turn to make it 3.5 or should i bump up my main jet to a 162 or something?

sry for the long post.

[MadMax27]

Sounds very slightly rich, but you r running stock components, so It should be fine. If you get a slip on, itll prolly be spot on....