As I disassembled my never-been-opened 2009 KLX-250S Carb, I had to drill out the plug covering the mixture pilot screw.
After removed the cover plug, as I was trying to find the original adjustment by screwing in first, but to my surprise, I found the screw already bottomed out!

This cannot be the original setting!? I must have changed the setting as I was trying to remove the covering plug - because I drilled a hole and screwed-in a wood screw "on the plug" trying to remove the plug!

The question is: What is the original adjustment??? As there is no way to adjust it while engine is running.

Thanks,
Karl

 

Does it matter since you need to change it anyway? General starting area is to put in a Kiehin 40 pilot for sea level up to around 4000ft elevation, 38 pilot for higher elevation (generality, I think I'm running a 40, but it's been a while). Then start idle mix adjustment around 2.5 turns out.

KLXter will probably pop in and fill you in with all the Dyno Jet pilot jet size used along with all the Dyno Jet stuff whether you're using it or not.