Is this some kind of joke? 125 main jet!

[ggodfreyX]

So my 05 400ex us bogging down just off of idle so it's time to adjust the fuel screw.
I bought the quad lat the end of last summer. I take the carb off to replace the pilot jet with a 42. I happen to look and there is 125 main jet on there. ???????? I live in Colorado and typically ride around 7500 feet elevation. I can't find any chart or document that would justify a 125 main. The quad is all stock except for a K&N air filter. Thoughts?http://i1167.photobucket.com/albums/q623/ggodfrey25/IMG_3006.jpg

[Crosshairs]

Wow...a 125 belongs in a 300 EX,not a 400 EX

[madmaxmodquad]

could it be a cheap aftermarket jet/ they got all kinds of crazy sizes

[Drfat400ex]

It shouldn't be a knockoff because it has the keihen K on it, but you never know with those crazy chineese things.

[DragonGunner]

Your main is probably spot on...you guys aren't looking at his elevation of 7500 ft. The higher you go the leaner you have to go on the main...the guy probably changed it because it was running too rich with the stock 148. I could be wrong since I don't ride the Mts...lol...but this seems to be what guys that have, have told me.

[hocman123]

it could be right i new somebody that moved from colorado to nj and his bike wouldnt even run and just let ot sit for years before he had some one look at it and they find he had a really small main jet with only about 1/2 a turn out on the af screw with the stock pilot jet.

the only real way to know whould be to check ur plug and see what it looks like

[ggodfreyX]

My Honda service manual states that if you are riding above 6500 feet you will need a 142. Since the K&N air filter lets in a lot more air than the stock filter I would assume to even go to a 140 or so. My local shop here in Denver does not even carry 125 main jets. It was not running hot so I am going to stay with it. I have an extra Vapor that I plan to use on this so I will keep an eye on it. I thought of the plug idea also but as soon as I bought it I changes the oil and put on a new plug. Does anyone know the default number of turns for the pilot screw?

[hocman123]

well u should be about 2 1/2 turns out on the a/f screw.

all u need to do even if it is a new plug is to let it warm up for like 10 min and ride it just a min or 2 the go into wide open throttle and hit the kill swich to shut the engine off when u are using the main and u will have some color to go off of

[ggodfreyX]

Thanks for the tips. I trying to get the quad in shape before or annual Moab trip in May!!!!