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Couple of carburetor questions yamaha wr400f 2000

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hi guys,


first of all excuse my bad english, i am from belgium ;-)


i bought a wr400f 2000 a couple of weeks ago and i it suffers from the dreaded iddle off bog.

Now i have read and read all about it at this wonderfull forum ans i got confident to open the carburetor up and give it a proper clean and try some of the solutions you guys bring here.

First i openend everything up and cleaned all the jets and blew them out with compressed air.

One of the solutions here is to change the leak jet to a #40. My bike does not have a leak jet. so that is not going to help. Checked the squirt of the ap pump and it is very strong. I inspected the ap diagrah and it is ok.

Next thing i am going to try is do the o ring mod now that the carb is off the bike. Hope it helps.


Now for my questions,


i noticed the timing screw for the ap pump is very much tightened, is it supposed to be that tight? See first pic


Second question, i wanted to remove the slot where the needle is (the thing that runs on the 4 wheels) don't know the english word for it. I can't get it out. Tried to screw of the bolt the bridge that levels the slot but the screw is torn out, any ideas? See second picture 


Third question, i wanted to install a adjustable fuel screw for easy acces, so i removed the little fuel screw and took it out. The spring came along but not the o-ring and the washer. So i looked in with a flashlight and saw nothing in there, is that possible? And can i just screw in the new fuel screw with the new o ring and washer safely?


Thx in advange





Edited by yvesdeclercq

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