Topic: Still confounded by accelerator pump

[fmctm1sw]

I got a pump housing today off eBay.  I added a photo to identify some areas.  My understanding was the passage I labeled with a #2 was only supposed to "conduct" in one direction.  I just tried the one I got and I can blow air throw that passage both ways.  Does that small hollow brass tube have anything to do with it?  Am I just unlucky or uneducated?

[CycleRanger]

Yes, there's a check valve there. A tiny ball bearing and spring. 
Recently I ran across an excellent tutorial on line how to fix a stuck diaphragm cover check valve. 
Unfortunately I can't find it again now.

[TwoTired]

They are low pressure valves expected to be operated by liquid fuel.  What pressures are you applying with air?
Behind the square block is a check valve ball which only allows liquids to flow in one direction.

I check mine with aerosol carb cleaner.

There is another check valve in the carb bowl, too.

What bike is this from?  I don't recall the small brass insert.

[crazypj]

If it's been soaked in carb cleaner, the spring may have corroded and cracked so it can't seal
 That looks same as Mikuni on late model RMZ MX bikes

[bollingball]

That does not look like mine either 78 750K. Got a photo of your old one? I would stick with it and clean the check valve on it and the bowl. If you can not get it to work with spray cleaner they are easy to take apart and clean in fact I would do that any way it is hard to get the crud off the ball without taking it apart.

                                         Ken

[fmctm1sw]

Gentlemen,  thank you.  This is off my 650.  I am just that unlucky but I was able to get that hidden valve free with carb cleaner and compressed air.  I started blowing through a tube with only "lung pressure" but I did blast it with air from my compressor eventually.  All was a go except that my tank gunked up my float bowls.  I am NOT going through this again so I'm going to get my tank stripped and relined or use a donor tank.

[tomkimberly]

When you get it all back togehter, don't forget to install a new rubber boot on the shaft. If you need one, PM me, I have a few.

Tom