Jetting Dilema

[roostonu]

Hey I just got a Big Gun full exhaust, K&N filter for my 05 400ex.Big Gun said to run a 42 pilot 158 main in bone stock trim with the lid on.Any ideas with the K&N and no lid?Do I need to change the needle?

[Lightninn]

I would suggest investing in a Dynojet jet kit. It will supply you with everything you need to get the job done and some good instructions on jetting it for the mods you have.

[roostonu]

I started with a D.J. kit and they recommended a 170 main & there needle on on the third clip.after looking at some of the other setups on this site that seems way to fat for what Im running.Comparing a 170 D.J. to a Kehin 158 on the chart.I ran the 170 at the sand drags in Pismo and 4/5th gear were totaly flat and the end of pipe was all black.Should I just stick to Keihen pilot and main jets?

[GPracer2500]

I prefer to stick with Keihin jets. The Dynojet needle might not work with Keihin mains so I'd stick with the stock needle too.

[zeppelin]

i prefer buying the individual jets too, your needle should be good, you might want to lower the clip one position though. if you have any more question check out my jetting thread in the how to section http://www.exriders.com/vbb/showthread.php?s=&threadid=221872

[roostonu]

Hey thanks for the feedback guys!I just got back from the Honda shop with some Keihen jets 158-162 and a 42 pilot.My only question now is my stock needle only has 1 notch,and Honda told me that may be do to CA. reg.You guys were saying that my D.J. needle may not work, you might be right.Honda says I have a pumper carb so Ill try the stock needle first.Thanks again.

[GPracer2500]

I think the 05' and 06' 400EX carbs come stock with a non-adjustable needle. You could shim it up if needed with little washers.

[roostonu]

Yeah I just talked to the mechanic at Honda shop and he gave me a little washerto shim it.The parts dude gave me the wrong pilot so now I got my bike torn down and sitten till Thurs.Bummer.Thanks for all the help.

[roostonu]

I found the reason the 05-06 400ex has a non-adjustable needle is because it has an accelerator pump much like you find on a Holley carb.I dont know that a D.G. needle wont work but Ill try the stock one first and ley ya know.

[GPracer2500]

The 99-04 carb also has an accelerator pump. The AP and whether or not the needle is adjustable have nothing to do with one another.

[2004exrider]

Wouldn't a '99-'04 needle work?

Jimmy

[roostonu]

Guess I got some bad info.

[Lightninn]

Roostonu - The jetting suggestions in the Dyno Jet kit are just a starting point that yes, should be rich. When jetting you always want to start rich and work your way down. That's the safest way to dial it in. Have you performed in plug checks to see if indeed you were rich with the settings you had with the D.J. kit parts? I've used the D.J. kits on several quads and have had great results with them.

[roostonu]

I didnt mean to make sound as if D.J. was no good,I just decided to go with the pipe man. jet settings.I actually just got everything back together,kinda late for a plug check.Hopefully the weather will hold up and I can try it tommorow.