Throttle hesitation question

[chadmel]

I am having a hesitation problem and was hoping I could get some input. I have a '03 400ex with a FMF Megamax Muffler(12 disks), Dynajet Kit with a 170 main jet, Dynajet needle with the clip in groove #3, the stock pilot jet(38), K & N Filter, air box lid off, fuel mixture screw out 3.5 turns, and I sit at 650' above sea level. OK, I'm going to try and describe the problem. When coming out of a turn I slip the clutch and right at the bottom is the hesitation. It seems to be worse when it's under more of a load. i.e. when it's super tacky out. My buddie has the same setup except for a White Brothers pipe and his does not do it. FMF recommends a 40 pilot. Would I be on the right track opening up the pilot? Any help would be greatly appeciated. Thanks in advance.

[trost66]

I'm not sure what to tell you

[chadmel]

Does anyone think it could be that my main jet is too rich?

[400rednEX]

i used to have that exact same setup except 18 disks and never had a hesitation on the bottom, does your accelerator pump work? my topend was real soft though, i went down to a 165 when i put my cam in and it seems about right now except i need to put in a 40 pilot.

[chadmel]

I think the pump is working. How can I be sure and is there an adjustment on it at all. As far as top end, it pulls all the way through pretty good. Do you think it sounds too lean or too rich? I think I am going to try going down on my main and see what it does.

[Nausty]

Originally posted by trost66
I'm not sure what to tell you


then don't reply....


I'm also looking forward to some ideas because I think mine hesitates to much on the bottem end too. 38 is stock pilot jet right? If its a bear to get started i'd go up a little bit.


One of my friends gave me a white brothers rev box and that made a HUGE differance in throttle responsiveness and power.

[ewalker302]

I think you are too rich, and you def hav too may discs in there for a stock bike.

I have dynojets and a megamaxx also.
My bike is pretty much stock-- I run 9 discs and use a 148dj main----lid off---uni---timing key.

I've tried lots of combinations & this works best for me.


:bandit:

[chadmel]

I'm going to try going down on my main jet and trying that. I'm getting off on a tangent, but I was wondering what you thought of that timing key. Noticeable difference? Thanks for the input.

[cals400ex]

Originally posted by chadmel
I'm going to try going down on my main jet and trying that. I'm getting off on a tangent, but I was wondering what you thought of that timing key. Noticeable difference? Thanks for the input.


hey, what part if IL you from?

the key will give you better throttle response. you won't really won't gain power besides a crisp power delivery. however, if you engine is stock, i would highly consider for the price.

if you interested in one, i have one for sale.

[chadmel]

Well, I went out and did some adjusting and here's what happened. First, i put a 160 main in; no difference. Next, a 155 main; no difference on the hesitation, but I started to notice a power loss through the whole range. Basically like it wasn't pulling as hard. Double-checked that the fuel mixture screw was 3.5 turns out. Next, moved the clip up on my needle one notch. Terrible idea. Not only did it not fix the hesitation, it was coughing and loading and wouldn't rev out. So I put the 170 main in; same result. Next, 165 main; same result. Finally, I moved the needle down th the fourth notch and put the 170 main back in. This is the best it's run yet. The hesitation is almost completely gone. There is still a little lag, but it feels more like a lack of power than a fuel delivery problem(if that makes any sense). At least now I can holeshot. Before, I would try to holeshot and it would just fall on it's face. I don't know if this makes any sense or if it's of use to anyone, but that's how it worked out for me. I'm hoping that when I get a different exhaust that gives a better power increase the "lag" will be totally gone. Thanks for the input.