Topic: accelerator pump linkage

[ffzcb750]

Has anyone ever had a problem with the throttle linkage not pushing down the rod on the accelerator pump sufficiently enough  to pump gas to the four carbs?  I have not been able to find  any previous discussion of this problem in the archives.    1978 cb750k

[Tdinova]

Did you try to manually push the plunger down to see the gas quirt? If it does not, it could be a blockage in the small tubes, diaphragm cracked.

[harisuluv]

Are you looking at the accel rod and literally seeing zero movement ie. no contact forcing it to move?  Keep in mind it dosen't take much if the circuit is primed for the mechanism to work.

How are you verifying it's not working or making contact?

[ffzcb750]

I rebuilt the carbs, increased jet size to 115,  (previously owner installed a 4/1 Kerker exhaust). Also I  installed new pumper diaphragm and the  little 'o' ring.  Manually the pump works and the lines to carbs pass air. 

The movement to the pump stem is only about  1/16 of an inch when carbs are installed on bike.    Is that sufficient to move gas to carbs?

 Bike still starts and runs pretty well when  completely warmed up.  I rode it from Phoenix Arizona to Anderson Indiana two years ago. 1800 miles

 Thanks to all and particularly harisuluv for his superb  diy posts.    ag

[lucky]

Has anyone ever had a problem with the throttle linkage not pushing down the rod on the accelerator pump sufficiently enough  to pump gas to the four carbs?  I have not been able to find  any previous discussion of this problem in the archives.    1978 cb750k

There is nothing to the linkage. But the two check valves better be working,especially the one in the bottom of #2 float bowl or none of it will work right.
1/16 of the pump rod movement is enough. If you look at the parts closely you will see that any more movement of that pump rod will just damage something.

QUESTION:
Did you look into each carb (engine off) and see that when you turn the throttle that all 4 spray nozzles squirt gas?
You will need air filters off and use a bright LED pocket flashlight to see what is going on.

There is no mention of this being done. That is why I am asking.