I bought this 300  with a China Keihin PWK 28 and worked okay but not run right but not lean on pilot 

So I put the original Dellorto 26 back on but it is lean on the pilot had a 35 I raised it to a 42 and it changed nothing I turned fuel screw out till it was going to fall out 

It still lean  no change I have cleaned and cleaned  I don't see the problem 

How does fuel get to the metering screw I see how it gets out into the venturi  not in  

Edited December 7, 20232 yr by Assgas

 There are two passages. One directly under the slide and one in front of the slide. The choke circuit also can make it run bad. Make sure all the lines in the float bowl are clear too.

1 hour ago, lineaway said:

 There are two passages. One directly under the slide and one in front of the slide. The choke circuit also can make it run bad. Make sure all the lines in the float bowl are clear too.

I see one little hole in front and the one for  the needle there is a real small hole sideways on the engine side there are clear 

I put all new  0 rings  in today  and then I could not start it the float bowl was dry  the float was holding the needle from opening  I had to tweak the arms so 

it would so it will let fuel in   It runs now much better 

Sounds like you cleaned it with carb cleaner and the gaskets swelled on the needle and seat. You have to dismantle every part off the carb and then clean. I usually just use contact cleaner to avoid those issues.