How the heck do I install this Throttle plate in my Carb

Hi All,

Was at the track the other week and the screw holding on the throttle lever popped off causing me to lose throttle. I ordered the new parts and have them on hand now, however I decided to take a look at the gold thing which I presume is the butterfly? I wanted to see if anything went wrong there as well. Now for the life of me I cannot figure out how to get the butterfly and it holder into the carb. I spent a solid 30 trying countless different ways to get it to go back but I just can’t figure it out.

Any help would be appreciated

Tank you



I know the diaphragm has to go in between the slit in the lever but I cannot get it to slide in and make it upright like it’s supposed to be.

The brass part go through the hole in tne shaft by the looks of it. Are you sure it is the right size? May only gonin one way.

Yes it’s the exact same on that came out when I disassembled it. Tried every which way, I could get it in but it wouldn’t close fully, it wouldn’t close past about 50% throttle

Put the shaft in and attach the clamp is it has one.
Slide the plate in
Manipulate the plate and shaft until the plate sits in the correct spot.
Place the screw(s) in the plate. (Small dab of thread locker.)

I suspect that your difficulties may be from not loading the return spring entirely before inserting the gold butterfly. The easiest way I found to reinstall is to remove the bracket that acts as the “stop” for the throttle lever/cam (depending on what style you have). From there you can:

  1. Affix the throttle lever to the throttle shaft while still outside of the carb. Use a small amount of blue loctite on the screw when installing.

  2. Test fit that assembly into the carb without the return spring installed. The purpose of this is to then test fit the butterfly and get a visual of where the throttle shaft is positioned for closed and wide open throttle positions. Remove the assembly once you are familiar, as you’ll need to remember these positions when installing the butterfly for real.

  3. With the throttle stop bracket still removed, fit the return spring to the throttle shaft and install the other end in the body of the carb.

  4. Rotate the throttle shaft clockwise until the spring is sufficiently loaded, AND you’ve reached a range where the spring is under tension through the operating range of the throttle.

  5. Position the throttle shaft to wide open throttle, and install the gold butterfly from the engine side with the stamped marking facing down and towards the airbox side. Orient the butterfly so it has zero resistance from the carb body throughout the entire range of travel. Install a small amount of blue loctite on the screw and tighten.

  6. Reinstall the throttle stop bracket and you should be good to go.

Thank you guys for all your input. Went out this morning and got it easily. It was just a case of working too late and getting frustrated, never thinking of a simple work around. Nonetheless I appreciate the help.

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