40mm Bing carbslide question

[StephenB]

I noticed that the position of both needles is about 20tho out. When inspecting the slide I found the tubes to be differently recessed, by ... 20tho. This isn't too noticable but I'd like to fix it.






DoI just head the slide body up and tap the steel tube slightly from the top? That seems to be the easiest.

Opinions? First hand experience?

Stephen

[StephenB]

Yes, you can, just did it.

[Major Softie]

Wow, that's cool that you were here for you.

[StephenB]

Sorry, couldn't wait!

[gspd]

So......How did you determine which was the correct one?
Maybe now they're BOTH out of spec.

PS> It won't make a discernible difference either way.

[StephenB]

You're probably right. I used the bottom of the slide as reference plane to make them both the same depth with respect to the (perceived) reference plane. And you're right I wasn't looking at absolute depth value. First impression was smoothness at idle and improved blip factor, which would make sense if I achieved same depth and position of needle relative to each other.

Do I make sense?

[gspd]

Do I make sense?

Yes, if you're building a Formula 1 car or spaceship.
On a airhead tractor carb? ........hmmm...
I guess being the same is better than being uneven regardless. No harm, no fowl.

Carburetors have fuel (mixture) and air (throttle stop) adjusters to compensate for any discrepancies in their actual parts, and to compensate for the fact that the cylinders they are feeding do not have identical intake and exhaust tracts and compression.

Just curious. how many degrees do you suppose the idle speed screw has to be turned to raise the slide 1/50th of an inch? (20 thou)?

[Major Softie]

ust curious. how many degrees do you suppose the idle speed screw has to be turned to raise the slide 1/50th of an inch? (20 thou)?

But that would also let in more air. If you adjust the valves at one end of the spec on one side and the other end on the other side, you can try to even that out with tuning too, but would you?

There may be no benefit in getting them right, but there's certainly no benefit in leaving them uneven.

[StephenB]

Just curious. how many degrees do you suppose the idle speed screw has to be turned to raise the slide 1/50th of an inch? (20 thou)?

I see your point, especiall the one with identical inlet and exhaust tracts. I wasn't thinking of the carbs being a overall "compensating" system. But as MS said, couldn't harm to get it right ... since I was in there already ... thanks for the comments.