Carb Issue

Eljeef · Post by **Eljeef** » Thu Apr 07, 2011 11:34 am

Hi folks. Just a quick question. Upon taking my carb apart (PW22) I discovered that someone had mixed up the idle screw and the air screw. It seems that the longer screw was put in the wrong hole and now the end of the shaft is bent like the crook of a finger. I tried to straighten it with moderate success but it will never have the perfect shape it once did. I suspect that the tolerances for that shaft fitting in the hole are pretty tight. I know I can get a kit from Tim McDowell but I am concerned that the wall of the carb within that screwhole may be damaged and a new screw would not do the trick. When taking the screw out, I observed that it was tight almost for the whole extraction. Any thoughts? Is my carb now worthless? Jeff.

davomoto · Post by **davomoto** » Thu Apr 07, 2011 11:54 am

Jeff,

It would be cheap enough to get a replacement screw, and see if it runs OK

Davo

Eljeef · Post by **Eljeef** » Thu Apr 07, 2011 11:56 am

davomoto wrote:Jeff,

It would be cheap enough to get areplacemt screw, and see if it runs OK

Davo

Dave, are these screws easily available in motorcycle shops or are they carb specific? Are they old JIS? Can you tell me which screw is the longer one?

davomoto · Post by **davomoto** » Thu Apr 07, 2011 12:07 pm

They are carb specific. The idle screw has a knurled head that sticks out past the threads so you can turn it by hand. The air / fuel screw has just the slot for the screwdriver past the threads. Post on the parts wanted section, someone probably has a couple laying around.

Davo

brewsky · Post by **brewsky** » Thu Apr 07, 2011 12:34 pm

On my CA77, both screws are slotted heads, with no knurls on the speed screw.
It is easy to interchange by mistake.
The air mix screw (on the left towards engine) has a tapered end, and the idle speed screw (on the right toward air cleaner) has a blunt, round tip.
They should both screw in and out easily, (without the springs attached) and if not, maybe they have been cross threaded or the wrong screws used?

Eljeef · Post by **Eljeef** » Thu Apr 07, 2011 12:55 pm

Here is a shot of the screws. Like Brewsky's; there is no knurl.
OK, no pictures for some reason. I'll have to play with that later. Brewsky, which screw is the longer of the two? That's the one I need.

Eljeef · Post by **Eljeef** » Thu Apr 07, 2011 2:44 pm

brewsky wrote: The air mix screw (on the left towards engine) has a tapered end, and the idle speed screw (on the right toward air cleaner) has a blunt, round tip.

OK, based on that explanation my air mix screw is the one that is damaged. It is longer and has a tapered end whereas the other screw is shorter and has a much more pronounced flat tip. Thanks Brewsky. I'll post a wanted ad for the screw in the "Wanted" section.