I finally got a chance to look at the carb again. I rebuilt it with a zenith kit, just for kicks. I got it all back together and once I put the new pump piston in, it wouldn't spring back to idle. I went back to the piston I took out, cause it seemed to fit a bit looser and had a smoother action. It was pretty good, but still not enough to to solve the issue. The pump moved easy enough that I knew it definitely wasn't the issue. So, I started looking at the return spring on the throttle shaft. I grabbed another original Bendix I had off one of my sportsters to look at it. When they made the change from the internal bar throttle (uses piano wire to push and pull) to the external, they definitely fitted it with a bigger, stronger spring. I swapped the bigger spring on, and problem solved. Now it snaps back instantly and closes the throttle 100%. So, my suggestion to anyone having this issue in the future would be to get a new throttle return spring, and keep in mind they did use a weak and a strong spring.

 

RacePres,

Is there a part number for the spring? I'd like to try a new spring.

 

27272-74 spring, throttle return.