Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
Screw should be around 7/8 of a turn out + or - 3/8 of a turn my own 350 are 1 turn out.
I just see you are running open pipes, this can affect the running as no back pressure, you may need to increase the size of the pilot jets to compensate, the information for the air screws is correct and turning them in will increase the fuel at low engine speeds but may not be enough.
Good to hear that you're getting some progress Erwin !Does the idle speed increase before it dies and do you still have the air screws at 2.5 turns ? If it isn't increasing in speed before stalling, it could be overfuelling slightly, so you may want to try running it a little weaker via the air screw adjustment and see if it improves - do the plugs look wet immediately after it stalls ?You'd expect to wind the air screws out to weaken it - more air = leaner mix, but I read an equally plausible description of the 400's Keihin idle circuit as posted by Hondaman on the US site that makes some sense and suggests winding the mixture screw out will actually richen the mixture as it's the air bleed that draws the fuel into the idle jet, and the greater flow or air would draw more fuel. Regardless of the theory, it's an easy experiment to do, so it would be worth trying an adjustment in small steps in either direction to see how the bike reacts. - and then let us know how you get on !It's also worth thinking about plugs - have a look at Julie's recent 400 idle issues thread that appear to have been improved by a change in plugs.Andy