setting carb

[ridinrednIL]

i live in central illinois. i have a 2003 400ex that was pretty much stock. i recently bought a white bros. mx4 slip-on silencer, UNI air filter, and removed the air box lid. I will be installing the silencer over the weekend. Wondering what jets to use,turns out on mixture,etc.. . Would be very thankful for advice.

[hornetgod13]

158K to 160K main jet will be a good starting point. I would recommend installing a 42K Pilot (slow) jet and setting the fuel screw to 2 to 3 turns out. If you leave the stock 38K pilot installed than the fuel screw should be around 3 to 3 1/2 turns out. Remember these are only starting points and should get you fairly close. You may need to fine tune your quad afterwards because not every quad responds the same way to identical jetting with different mods, altitude, and temperature. You can buy keihin jets at www.jetsrus.com

[Honda#4]

Try a 155 main and put in a 42 pilot. 160 is way rich and a 158 is just a tad rich for a slip-on. Turn your screw out 2 1/2 turns, and put the needle in the 3 slot from the top.

[ridinrednIL]

thanks!! white bros. recommended the 155 main, but wanted to double check!!

[Honda#4]

155 main will be right on, you will have to adjust your fuel a bit to get it spot on. Your welcome, if you have any other questions just post a thread or shoot me up a PM and i'll get back to you.

[hornetgod13]

With the air box lid OFF a 155 would be better and a 158 might be closer if it's colder where he rides or it's near sea level.

[Honda#4]

I run a 42 pilot and a 155 main in below zero weather up here and I have no trouble, all I do is adjust the fuel screw to what ever the temp is and it's fine. Illinnois is only one state down from us I think we almost have the same temps.

If your confused just buy jets from 155 to 160 and try it, only way to learn.

Whats your temp out?