[kdahl524]

I have been using these forums for a long time but have never posted my own, This time I can’t seem to find the answer to my question.

I have a 2006 250x, brought it 7 years ago from the original owner. Original owner put in a stage 2 hot cam, did the airbox mod and appears jetted accordingly. Bike ran great until about a year ago then began the hard to start sequence. So I went ahead and replaced piston rings and piston with OEM and shimmed the valves. While doing this got an all balls carb kit and cleaned the carb replacing the seals and leaving the jetting that was in there but cleaned them thoroughly. The kit came with the thumb screw type mixture screw so I went ahead and swapped that instead of keeping OEM.

put everything back together bike started right up and ran like a dream for two rides, then the mixture screw fell out (learned after the fact I turned too far out). Ended up getting busy with life and the bike sat for a couple of months before just a week ago installing the new mixture screw (OEM) and tried starting the bike. It would not want to start took carb back out and checked the Jets pilot seemed a little dirty so cleaned that up and put back together. Bike sounded like it wanted to start but wouldn’t keep running. Turned the idle up and it fired right up. But the idle was extremely high. I let the bike warm up and took it for a small spin down the road before trying to set the idle correctly. When I got the idle set correctly I killed the bike and tried to restart, the problem persisted. Wants to start but won’t with the correct idle speed, if I crank the idle speed back up it’ll start up with some hesitation.

I’ve checked boots on both sides of the carb and they appear fine, hot start looks to be ok but the pain it is to truly take out I have not taken it out to fully inspect. Compression test showed 60 psi, have not performed a leak down test yet have a tester in the mail.

I love this bike and now my little one is riding it’s killing me not having my bike going as well.

[JimDirt]

Welcome to the site !!

Did you check in the hole for the Fuel Screw and make sure that when the screw fell out , that the old O-ring is not still in there ??? , I have seen the screws fall out (from doing the same thing you did) and they did not check to make sure everything was cleared out before installing a new one ...... It should be spring , flat washer ,O-ring , O-ring being the last to put on , sometimes when the screw falls out the washer and the O-ring stays in and at first glance it looks normal till you shine a light and/or use a magnifying glass to see the O-ring is still there , if it is and they are double stacked , it won't run very well ............. That would be my first guess from what you described ............

If you are using gas with Ethanol in it , then it can and will clog the pilot jet , especially if the bike sat for more than a month or 2 , these bikes do not like old gas , so make sure your pilot is clean , and make sure the gas is ALL fresh , drain it over the winter and run the bike till it runs out of gas , or just drain the float bowl before putting it away for longer than a couple months .......

One other thing , you said when you rebuilt that you "adjusted" the valves , but did not replace them ....... so have you rechecked the valves ??? , once the Intakes start closing up , it means just that , they are starting to close up , and will do so over and over with each adjustment until there are no shims small enough , then your done and need to replace them ..... if the valves started moving , then there is a good chance they have moved again and are tight , anything under 0.004 and the bike will struggle to start , once they close more then that the bike will hardly run at any RPM , once they completely zero out , the bike will not run at all .....

[kdahl524]

Thanks for the fast reply!

I did check the Oring status and it did not look like it was in there but did not verify with magnifying glass so I will double triple check that.

I did drain all gas and replace with fresh and cleaned pilot after empty and before getting new gas into carb.

Valves were my first check once I tried and failed to start. They are shimmed .004 which was as close as I could get with shims when I shimmed during the rebuild. depending on what the leak test shows I’ll be doing a complete valve job now or wait until they drop below spec again and do them at that time.

Thanks again!!

[JimDirt]

No problem ..... hopefully (not really) it is the valves , and once that is fixed the issue will be solved ...

And on the O-ring , if the washer is still in there you have to look really closely , and maybe even use a pick (like a dental pick) and poke around and see if anything moves , but looking with a magnifying glass and a bright light , will also allow you to see if there is in fact a O-ring under a washer , it is easily missed as they get stuck most of the time when removing the fuel screw and all you get back is the spring ..... real common occurrence .....