Hey guys first post!

My 2007 KLX250S has some issues, it likes to surge when you try to hold a constant rpm, either in neutral or in gear. And also when you snap straight to WOT from idle it stumbles before revving up. It has new gas, new spark plug, and fresh 93 Octane, I also cleaned the carb this past winter.
The temp was about 45°F the bike had been running for 25 minutes, I used the idle adjust screw to set it to 3000 RPM and you can see it goes above and below that a few times. Video Link: 2007 KLX250S Running

 

First question is if it has been properly jetted. As lean as the KLXs have been, that could be your problem. The 93 octane gas won't do jack for your bike and problem. For proper jetting using Keihin parts you can refer to d pippin's web site here.

If it is properly jetted you might still have some crud in the carburetor.

 

But these are supposed to have 93 right? I remember it saying it somewhere on the bike.

 

And also what jets do you recommend, right now on Long Island I'm at 13' above sea level, but soon I will be bringing it to my house in Pennsylvania where the average elevation in the area is 1000'. I'm not sure if I should wait and see how it runs up there, what do you think? I've never re-jetted anything.
Thanks.

 

The Pippin jetting information for the CV carb was plug and play for my brother's 06 and my 09 and we're around 1000 ft elevation. He went with the larger main mentioned, where I went with the leaner one and used a Dial-A-Jet.