Cough drops for my 400ex

[EXtreme-]

I'm in real need of some jetting advise from someone who is experienced with the Pro-meg system. I can't seem to get rid of the cough that occurs during the 30-40% range of accelleration. There seems to be a sweet spot that the hesitation loves...and happens most often during 2nd or 3rd gear take-off. This really blows at the foot of a hillclimb when the power stalls for a split second. Once past this point, it's a raped ape! The main jet is perfect at 158 and has been fine tuned by trial and error. The pilot was replaced with a 45....not sure on the carb screw adjustment turns....as to how many out. The needle is raised (richer) one position from stock. Also, running 12 discs.

I did a simple test to remove the airbox lid (got a k&n with no prefilter) and the problem went away for the most part....at least it was improved some. The only problem is...I refuse to run without a lid or one with holes in it due to the conditions that I ride in.

Heeeeeeeeelp!

[EXtreme-]

no replies

[4punksdad]

could be alot of things........if you have done all of that & have a stock airbox lid, I would say she is lacking air. I hate to sound like a broken record, but try this. I treated the fabric with scotchgard which makes the water bead up & run off before it can enter the airbox. So far my filter has been as clean as if the lid were not drilled. I ride in alot of stream crossings, mud, dust, and fields w/tall grass.

[Leo]

If removing the airbox lid cured the problem, then one of your circuits is likely rich...

I'd be tempted to put the needle back to stock and give that a whirl... If that didn't help then I'd probalby try a smaller pilot 38-45 seems like a big jump to me?)

I'm still trying to talk the crew inot the trip in september, maybe we can tweak it then

Leo

Yeah what's the reason for the replacing the pilot in the first place..I put a different header pipe on mine and that required me to go to a 40 but I don't see a reason for you to go larger maybe a 40 but not a 45...changing the position of your needle was correct but adding a new pilot I think is your problem...put the 38 back in and see how she runs..

[EXtreme-]

I've had the promeg on for quite some time now, and recall having a hard time finding pilots. A mechanic had a stash of jets and offered me a 45 and said to just dial it in with the screw. I never did fine tune the problem since installing the 45. I do remember that the 38 wasn't cutting the mustard.

I'm to the point now where lazyness to tear it apart vs. hopping on for a ride is switching roles....it's time for the tool box. I wouldn't want Leo to cook me in a drag at Sproul because of my jetting

So....ya think a 40 or 42?

[EX_RIDER]

I also run the pro-meg exhaust as you know.I am about the same alitude as you I think.the only think I changed in my jetting was the main jet.I just put a 155 in her and she ran great!!I have no sputtering what so ever and a nice looking plug.There is a small loss in low end,but my mid and top is a killer also!There is only a little hesatition only after it is started and it stops when it is warmed up and ready to fly!!


When are you leaving for your trip?And were are you meeting at?I was down West Vigrina riding sunday and it was great.Some nice hills there.I went up on called the wall and the last 6 feet are vertical.The last person to try it on a quad broke his neck and I wanted to prove to my buds that I had a big sack to back up my mouth!!they all chicked out to even go down it.

[EXtreme-]

Well, I just got off the phone with the carburation dept. at White Brothers. He said to first go back down to a 40 pilot and test it out. Then possibly change the needle back to stock height as plan B. She's definately rich....just have to do trial and error.

EXRIDER, leaving for Hatfield/McCoy over labor day weekend and Sproul state forest on Sept 14,15,16. (coming?)

GO to a 40 pilot,,Denniskirk has them, and either put your needle back at stock,,,go from there but I think you'll be OK,,maybe adjust your airscrew 1/2 turn either way,,,and remember to let the bike run for at least 10 minutes before you do any testing..or adjusting..