Jetting for sparks

[Mofo Racing]

I have did a search and couldn't find a clear answer. How about some help with my jetting.

Sparks x-6
K&N airfilter
airbox lid with White brothers 1-inch filtered holes
wb rev box
right at sea level (louisiana)


hope I didn't leave anything out

[cals400ex]

try a 155 to 158 keihin main. needle in stock or 4th position. a 40 or 42 pilot jet should work just fine.

[Hotdog]

i just got off the phone with sparks. they told me 45 pilot, 2 1/2 turns and 158 main.

[cals400ex]

Originally posted by Hotdog
i just got off the phone with sparks. they told me 45 pilot, 2 1/2 turns and 158 main.

i tried a 45 pilot with my setup and it was too rich. if i let the bike sit and idle for a minute or so the plug was totally black. i ended up using a 42 pilot with 2 turns out on the fuel skrew. i know at idle i wasn't really lean because my headpipes didn't glow at idle.

[cals400ex]

i think sparks varies the answers a little too. with your setup they told me to run a 152 to 155 with the lid off. however, my elevation is a little higher than your but not too much. also, temperature outside makes a difference too. in the colder months, you need richer settings than in the warmer months.

[Hotdog]

i added a sparks exhaust and i been having problems ever since. when you start it, you have to hit the throttle about ten times and it bearly starts up. but then it stalls out like its not getting gas. the plug is dry. if i keep stabbing the throttle it will stay running but only if the choke is on and its missing the whole time.

[cals400ex]

Originally posted by Hotdog
i added a sparks exhaust and i been having problems ever since. when you start it, you have to hit the throttle about ten times and it bearly starts up. but then it stalls out like its not getting gas. the plug is dry. if i keep stabbing the throttle it will stay running but only if the choke is on and its missing the whole time.

you need to put in a larger pilot jet and/or richen up your fuel skrew