Topic: 74 CB550 Throttle Arm Missing Part Help

[bobbo138]

Finally getting around to putting my carbs back together after taking them apart to clean them and I'm missing a small piece that goes into the throttle arm linkage that raises the slide.  I'm guessing they're unobtanium but I thought I'd ask here if anybody knew of a replacement or comparable part.  The part is circled in red in the attached photo.  Thanks for any and all help.

[bryanj]

Only way to get that is from a junk set of carbs

[carnivorous chicken]

I've got an extra carb or two from a set of 069As, including one with a broken float tower. I can see if it's in there, I imagine it is.

[bobbo138]

Bryan - that’s more or less what I was expecting.

Carnivorous Chicken - that would be amazing and much appreciated. My carbs are 022a’s but I can’t imagine Keihin used a different part for such similar carbs.

If that doesn’t work out does anyone have any thoughts on making a replacement? It’s a simple part with a concave face to interact with the ball on the rocker arm. It acts under light compression force between the nut on top and the spring pressure from below. I’m thinking I could make one out of some brass or maybe delrin? I could also 3D print the part. I’m more concerned with the friction between the part and the ball joint as it’s acted upon with every twist of the throttle. Anyone with more material science have an opinion? I really appreciate everyone taking the time here to help.

[jlh3rd]

is this it?...not cheap.

[Ozzybud]

It is.  Its inside the tubular shaped link under spring compression.

I am surprised there is not more talk on here of those coming up missing. I learned the hard way long ago when it fell out down into the slide when changing needle position.  The bike ran very poorly and would not sync. Luckily I found it and was  able to get it back in place. Now I always get them out and put grease on the top so it stays in place when resembling.

[carnivorous chicken]

Bryan - that’s more or less what I was expecting.

Carnivorous Chicken - that would be amazing and much appreciated. My carbs are 022a’s but I can’t imagine Keihin used a different part for such similar carbs.

I'm out of town this weekend but will check when I get back Tuesday AM. I actually have friends from the USA who will be in town and if I've got it maybe I can talk them into mailing it when they get back...

[carnivorous chicken]

Bad news -- I looked at the spare carb bodies I have and that piece is missing from both -- sorry about that...

[bobbo138]

Not a problem.  I appreciate you taking the time.

Anyone have any thoughts on a suitable material for a replacement part?

[Ozzybud]

Not a problem.  I appreciate you taking the time.

Anyone have any thoughts on a suitable material for a replacement part?

I think Brass would work. Definitely something softer than the ball arm.
All the originals I have seen appear to be steel. Black finish.
I find it hard to believe someone on this Forum doesn't have a box of crap carbs in a box somewhere. I have a box of carbs but none with this linkage

[bryanj]

Let me look in what is left of a box of 400 bits and see, cost you postage from UK though