DOHC 10.5liters/100km

[overpl]

nope - choke is out because I pull it out manualy directly from carbs every time i run ;-) damn - can somebody make a photo or show it on some web photo?

 

[Edward]

This is where the idle screw is located. Based on your signature, I would guess that the idle mixture screw looks a little different on yours.

http://www.flickr.com/photos/7979944@N04/4689682730/

I think this is more like the one you have:
http://www.thegsresources.com/images/carbs/025_Prepare to remove air screw.jpg

If I remember correctly, if yours is the bottom one and hasn't ever been adjusted, there might be a brass cap on it that needs to be drilled out. Might not be applicable on your bike. The idle mixture screw is the one being adjusted by the guy in the picture.

 

[overpl]

Thanks I'll look into that - is this screw adjusting mixture when idle or mixture in general??

 

[Edward]

I believe the Idle/Pilot mixture screw has effect at all levels of throttle, but its effect is most noticeable down around the 0-25% level.

http://www.iwt.com.au/mikunicarb.htm

 

[overpl]

guys - u R irreplaceable
Can somebody tell me what is your float height at DOHC XS400 and how you messured it? There are 2 ways to do that and its going to have like 3-4mm difference