Jetting help on 250x

[honda400ex27]

Hey i need some help on a buddys 250x..

It has been way to rich, and i rode and went through the throttle and from 3/4 to full it wouldnt open up, just spit and sputtered, so i went for a smaller main jet, went from 125 to 120..that fixed the problem as far as main jet and opening up good.....Now the problem is wont idle good, and sometimes through mid range when it needs to pull up a hill it cuts out and sputters...does it maybe need some needle and pilot adjustments....it only cuts out when u wanna pull up a hill or bank, as far as flat road it will go fine..or could it possibly be motor, maybe firing, or valves and timing?

[cals400ex]

it could be a problem with the float if your only having problems in hills. i know the 400ex's had a similar problem as this until they fixed it in 2001.

[wilkin250r]

Idle is strictly the pilot jet.

First, check your basics. Make sure you don't have any air leaks in your intake boot, make sure your carb is clean, you have fresh gas, and a new spark plug is always a good idea.

For the idle mixture, start with the recommended settings (I think it's 1 and 1/4 turns out) Set the idle speed way up, and start playing with the idle mixture screw until you find a good setting.

The mid-range mix is the needle clip, and it sounds like the clip is too low (the needle is too high) so it makes your mid-range too rich.

If you analyze HOW you are using your carb, it can sometimes help to diagnose these problems. It sounds like you are OK on a flat surface, but it sputters going up hills? Typically, when going up hills, your carb is a little more open than a flat surface because you are loading your engine a little more, which will aggrevate a rich condition. I would raise the clip up one notch (which lowers your needle, leaning out your mixture) and see how it runs.

Let me know the results.