Topic: PD carbs accelerator pump passage issue

[sharpinski]

Hey there, I have a 1978 CB750K with PD carbs. A new problem developed with the fuel passage from the accelerator pump. Fuel gets through the bowl section just fine, but shoots out between the bowl and carb body when throttled. I tried shooting carb cleaner into the brass hole (in the carb body) that feeds the brass spigots in the mouth of the carbs, but, after many tries, it doesn't change a thing. The flow definitely stops at the brass inlet hole in the carb body. I dismantled the carb bank to shoot carb cleaner through the side brass nipples that carry fuel to each carb spigot. In other words, blocking one side with my finger and spraying through the other side (if that makes sense). The carb cleaner shot out the spigot in the mouth of the carb and through the brass inlet hole. For some reason I can't get carb cleaner or fuel to go through the brass inlet hole in the right direction. It only shoots through in the opposite direction. The bike was running great before this started happening. What drew my attention to it was a sudden high idle. Anybody come across this before? Any help would be great. I hope it makes sense. Difficult thing to write about. Thank you, Steve

[BobbyR]

You will need to pass a strand of copper wire or a high it E guitar string through it. Most times it need mechanical clearing. You run the wire through and spary with cleaner, then run it through again and then flush.

[sharpinski]

Does the diameter of the wire or guitar string need to be quite a bit smaller than the hole? I've tried a wire that goes into the hole fine, but it immediately stops and I can't push it any further. It's like trying to push a wire into a hard metal surface. When you say through should I be able to get it into the spigot? Thanks for your input Bobby.

[flybox1]

that tiny hole in the brass plug is a b*$@h to clean.  go in from the nipple side, too
an ulstrasonic cleaner is really the best way, as there is a sharp turn to the brass nipples between the carbs...  debris in there needs to be physically dislodged.
poke around with a guitar string as suggested, and keep going with the carb spray.  you'll get it.  it should flow both ways.  no check valve in there.

[Don R]

 My brother took a chance and pulled a brass insert out with pliers on his. He got it clean then and running good. Then he let them sit a couple years and now I own the bike. I haven't tried starting it yet. 

[johans]

Had a last acc. pump nozzle that would not come clean until i took some MAF sensor cleaner and 2 pieces of shrink tube to the straw and blew it out . Worked great .     

Note : remove the carb to carb fuel lines in between the carbs to have the foreign debris blow out , ( they are attached in this pic)

[flybox1]

Yeah....good hack, johans!

I heated and bent the tip of a sewing pin 180deg.  Dislodged whatever was stuck in mine..

[brewsky]

Or...….
1 earwax syringe
1 small o-ring
small piece of air line hose
sea foam