Super8 50 2T carb idle mixture

[eamartin]

Parts diagrams show an idle mixture screw with a slotted head for a flat blade screwdriver on this Keihin PB carb.  My carb has what I've always presumed to be a brass plug in this location.  The presumed plug does not have a round head as others I have seen.  It is sort of D-shaped, with the flat side of the D positioned at about 11:00 in the attached photo.  Does anyone know for sure what this is?  Thanks

[netlag]

sorry for the necro...

d-shaped carb screw (bit) is ... Air Screw (AKA Idle Speed Adjuster).

example of tool for it..

Motion Pro Replacement D-Shape Bit for Hex Driver  - 08-0242  Dirt Bike Motocross |
Dennis Kirk https://buff.ly/2rsAmYp

Noticed that some tech without the bit... make an adjustment using a flat-blade screwdriver to adjust it. Seen others even make a homemade tool for it.

Lastly,

Flat blade screw to it's right is called Throttle Stop Screw.

[eamartin]

Hey, netlag!  I had forgotten about this post (12/20/17).  Thanks for setting me straight on this unusual-to-me screw head (not a plug as I had presumed).  eamartin   

[netlag]

Was just reminded of the epa caps recently as I went to adjust the carb on my scoot. Learned of the d-shaped screw after the brass cap was removed from above it.

Was interesting to see all the work around people have used, was just sharing what I learned.

[eamartin]

netlag,  I finally got back to working on my scooter.  I bought the D-socket you recommended and removed the adjusting screw.  This enabled me to confirm that the slow jet passage was once again blocked.  Thanks for the tip on the D-socket.