Topic: 77 accerator pump on carbs

[CB750R]

Hey all, I've just attempted a rebuild on my carbs and having some issues.... (sounds common eh)  I can see how the accel pump lever attaches to the main carb actuator thingy, but with what?? I seem to either misplaced the (I assume spring) that attached the two, or it never had one?  anyone got any ideas? I had to use a screwdriver to "prime" the bike to convince it to fire up, and as I read the available threads this little pump is much needed.  Second, post rebuild and firing it up, she sorta idles ok but then runs up to 3000 and wont settle down?  need a synch?? or somthing obvious I'm missing?

Much greatfull for you help

[eldar]

First, the accel pump is not needed for starting or idling. It also does not attach to anything. There is a tab on your carb rack that turns as you turn the throttle, this tab pushes against the pump rod. This operates the pump.

There should be a small gap between the tab and the rod, about .014 inches or something like that.  If you need to prime using the accel pump then you are set way too lean. This could also explain your high idle issue.

As you run out of gas, your RPMs climb until all fuel is used then the engine will die.

You need to set your idle screw out about 1.5 turns and make sure the air cleaner is on.
You should also have your carbs "bench" synced with all slides open to about 1/8 inch.

[CB750R]

I have the  lever thing that would atuate the pump rod, but how does that attach to the main carb actuator?? right now it just sits there doing nothing. the cables make the carb work, and such but nothing ever moves the lever for the pump, it looks like theres a post on the main carb actuator to link a spring or something to the lever but I dunno how...

As for the rising rpms, good call, I left the pods off... thanks

Grant

[CB750R]

yeah looked up schematic on servicehonda site, there was a spring, anyone wanna measure theres for me??? i might give a rubber band a twirl untill I get the right one in there. 

[the_genrl]

ohhh i see what you mean.  yes, theres a tension spring that the throttle shaft is connected to. You should see matching little notches where it should go right on the peice that pushes the rod and on the throttle shaft.  I'd go to the dealer for that becuase it does have a special tension and other universal springs dont work as well, ive tryed!

 I couldn't understand what you were talkign about for some reason, im a little slow .

[the_genrl]

doh!  too late!  yea, i guess just try a rubberband for now.

[eldar]

There is NO spring for the accel pump. The rod for the pump does NOT connect to ANYTHING.
Now that tab itself though may have a spring on it, I have not looked at that part since I adjusted it but I DO know there is nothing that the pump rod attaches to. The tab pushes the rod and that is how the pump is operated.

[CB750R]

Thanks genrl, you got it, the servicehonda site lists that whole assy with the linkage, and the spring together, so I'm not hopefull they'll still stock it... so if anyone has a measurement, of the spring incase I need to get creative, that would be awsome. 

Eldar, thanks, but we're talking about the little arm that makes the pump work, I realize that the only spring that the pump has is the one providing pressure on the diaphragm.

[eldar]

Ok I just wanted to make sure since the arm DOES have a spring but there is nothing that connects the pump rod TO the arm. The arm pushes against the rod. I just wanted to make sure we  were on the same page.

[CB750R]

thanks again for the reply, I personally think the next carb service is going to be handled by someone else, I think I lack the patience for these things!!

[jtb]

Grant,  I'm going to pull my carbs later this week after I receive the nos petcock I just bought.   I'll measure the spring then.  I don't have an extra, as the original carbs didn't have one.  I used the one from the set I bought for parts on my bike.

John