jetting problems

[danpuska496]

Somebody help me. I just got brand new hmf slip-on silencer for my bone stock 02 400ex. I got the silencer on it, put the recomended 170 main jet on it, raisedd the needle to the recomended 1st clip, and turned the fuel/air mixture out the recomended 3.5 turns. I put it back together and tried it out. It idled great, acclerated great but a few rpm's before i'd shift it up it starts to spit, sputter and basically run like shizat. The only other mod is four,1in. diameter holes in the air box. the lid is still intacted and the bone stock filter is still breathin in my air box. I have also removed the snorkel and patched the hole with a piece of sheet metal. i need some help guys. HMF must have messed up someplace cuz me machine sux at high rpm's. If anyone could recommend something for me i'd appreciate it.

[AtvMxRider]

I'd say the 170 is a bit much for just a slip on. I'd drop the needle down a clip too.

[cals400ex]

try a 155 main jet with the needle clip in the stock 3rd position or the 4th position from the top of the needle.

[hondarider2006]

Originally posted by cals400ex
try a 155 main jet with the needle clip in the stock 3rd position or the 4th position from the top of the needle.


When it comes to Jetting...listen to this man, he is almost ALWAYS right, and he does know what he is talking about;)



You can't go by a chart that tells you what to jet by, because I can almost garentee that its going to be wrong. Its just trial and error w/ jetting. I would say start at a 155 and move the clip back to the 3rd notch, 4th may be a tad rich. BTW did you get a jet kit, or are you using stock jets?

[cals400ex]

Originally posted by hondarider2006
When it comes to Jetting...listen to this man, he is almost ALWAYS right, and he does know what he is talking about;)



You can't go by a chart that tells you what to jet by, because I can almost garentee that its going to be wrong. Its just trial and error w/ jetting. I would say start at a 155 and move the clip back to the 3rd notch, 4th may be a tad rich. BTW did you get a jet kit, or are you using stock jets?

thanks man

yes, i guess we better find out what jets he is running. :eek: i just assumed it was keihin jets/needles.

he didn't mention where he was located, his eleveation, the temp, etc so i told him to try a 155 and go from there.

[hondarider2006]

sounds like a good starting point no matter where you live....I am running a 165DJ right now...but I think I am a tad rich. It was fine all through the summer, so I am thinking I may be a tad rich now. God I hate jetting:mad: :rolleyes: