400ex carb jetting

[MikeRWK]

Im wondering what jets to run in the 400ex carb i just installed, im at sea level i can throw a rock from my house into the water.Bike is bone stock other then the carb and K&N filter.

[PA250x]

I was under the impression that the stock jetting on a 400ex carb was good for stock to mild 250x/300exs. There are tons of posts on this, try doing a search. I am sure you will find all the answers you are looking for.

[MikeRWK]

Maybe i just need to adjust the idle mixture screw then...

[PA250x]

What is the issue? It won't idle? If it won't idle, then yes, I would say adjust the idle some and that will probably help. How much adjustment all depends on if it idles at all. If it does idle for a little while, but shuts off, then just adjust in small increments. If it won't idle at all, then you have to go a full turn or so. Good Luck!! Post up to let us know how you make out.

[MikeRWK]

I have the mixture screw out 1 turn and its shootin gas and flames out the carb, im at sea level and the carb came from ohio which the lowest elevation there is 455 feet above sea level im thinking the jets are wayy too big, would it run if i installed the jets from the 300 carb?

*edit* i put the stock jet in the bike starts now anyways.

[MikeRWK]

This bike is a beast now! It just wants to stand right up in 1st and 2nd. But it keeps sucking the choke closed? im using the 300ex air tube maybe is that the problem?