Calling all carb guys.

[Sapper]

I have an 03 KX125 and having one helleva time getting out a bad bog/sputter. Currently it has a FMF pipe with 400 main, 37.5 pilot, clip in middle.

Last year I had this issue and moved clip to top position. This time, after a topend rebuild, it's worse than ever. We just now put it all back together since last October. I'm currently trying to adjust the floats. But when I set them to 9.5mm, it will start and run but can't refill fast enough so the bowl runs dry. If I raise the floats, it gets fuel but the bog is back.

9.5mm +/- .5 is the specs. I tried 9mm and still ran dry, 8.5 starting to sputter but showed a sense of running dry with hanging idle. 8mm, sputtering but doesn't run dry as bad.

I've read alot of different articles on this but, in the end, no one ever posted what they did to fix it. I met a guy last night who has the exact same issue with his 03. He was asking me and said to let him know what I figure out to fix it.

Anyone here have any previous "altercations" with this bloody bastard

[Friar-Tuck]

 Hey Sapper,
 Have either of you guys tried one of those boyesen "Super Bowls"?
 http://www.motorcycle-superstore.com/2/10/215/8212/DPITEM/Dirt-Bike-Motocross-Float-Bowls-Boyesen-Super-Bowl.aspx

 It's supposed to have a larger capacity and help prevent the fuel from "Frothing"  ?!
  Best of luck my friend!  Tuck\o/

[SS109]

A 400 on the main?!

[Friar-Tuck]

It has the Mikuni TMX38x carb  (400 main)

 Sapper, have you had a look at the screened filter tube in the tank (petcock inlet) and that the vent in the fuel tank is clear? 
    What I'm thinking is a possible restriction in fuel flow.  I am by no means a fast rider, but my 500 runs on my keihin 38 with no problem,  for a 125 to run the bowl dry it seems the fuel level must be in the bottom 1/4 of the bowl, no? 

Please don't take offense, as I know you have been supporting your racing program for years and are by no means a rookie!
   Tuck\o/