flat slides in a round slide... flat vs round

I had heard of flat and round slide carbs though I didnt know what the difference was. Today I looked at the old diaphrams out of the previous set of carbs on my bike (ones with seized pilots) and noticed the slides were flat on the bottom where the ones in my current carbs were round on the bottom. I then swapped them over but havent gone for a ride yet. I was doing research but havent found alot about the difference except flats are usually used on drag bikes and that flat slide carbs are usually a bit shorter than round though i believe both these sets are the same exact size. I will check to be sure... Guess I'll have to take it for a ride and see how it goes while i wait for some information on these things. Thanks in advance....

You have CV round slides.
The half moon cut out on the bottom of the slid(e) is for tuning.
Look at the hole in your carb(s) with the (s)lide removed.
Is it a round hole or a slot?

If you have diaphrams you have CV or Constant Velocity Carbs. Flat slide carbs have more of a plate that slides up and down and round slides have a cylindrical slide when viewed from the top looking down.

You are correct they are cv carbs however this seems to be an interesting twist. The carbs with the new slides installed look like this :



However the Old slide is this one :



Now Both the old set of carbs and replacement set of carbs are bs34 mikunis with these slides and stock jetting being the only differences. It seems cv carbs typically have roundslides however mikuni made flat slide cv carbs for a limited time, often reffered to as "slingshot" carbs. Seems they were also highly favored. If anybody has heard of these slingshot carbs before let me know. Carbs are pretty new to me so obviously this is news lol

It's hard to see in the photo, but it still looks like a curved face. The cutout on the bottom is not what makes it round or flat. It would require a photo from the top down with the cap removed.

Not sure about kawi applications, but yet, there were CV Flat Slide carbs from Mikuni:

www.motorcyclecarbs.com/Mikuni_OEM_CV_Carburetors_C682.cfm

"T" indicates flat slides.

BST CV Carb Diagram:

www.motorcyclecarbs.com/Mikuni_BST_Carburetor_C685.cfm

The actual slides are round in shape, I must be misunderstanding round vs flat slides here lol The difference Im reffering to is easily seen here :



The comparison shows the difference in the bottom of the slides, one is a half moon shape while the other is round. I thought from what I found the flat bottom slides would make them the slingshot cv carbs and the half moon shaped bottoms just typical cv carbs. Im not too sure though. It seems the flat bottom ones would be better for airflow and possibly even response seeing as they must be lighter without the half moon bottom? Looking with the diphram cover off they are round slides with round diaphrams and a round tounge one on side for lining it up.

[quote=" I thought from what I found the flat bottom slides would make them the slingshot cv carbs and the half moon shaped bottoms just typical cv carbs.[/quote]

What do you mean by slingshot?

BS34s came with both,flat and half moon.
If I remember right,being miles from home right now.

I found some old info on a cv flatside carb called slingshot carbs. Thought these slides made them sol.

A round slide is cylindrical, with more or less cutaway at bottom on intake side.
Depending on carb design, may be manually operated or vacuum operated.
When vacuum operated, carb is referred to as a CV or Constant Vacuum carb.
Lots of different manual slide carbs.
And lots of different vacuum slide carbs.
All with Round Throttle Slide --




Flatslide is rectangular.
Lots of different flatslide carb designs.
Here's one of them:

Flatside throttle slide --



Good Fortune!

Okay I get it now, its actually an entirely different design. Not having known what the difference between them on top of seeing these two varying slides really threw me off. Now that its clarified for me, wouldnt you still think the flat bottom design is better than the 1/2 moon? Less air restriction/disturbance I would assume. It does seem to idle better as I couldnt get it to idle below 1500rpm before and I got it down to around 1250. Also throttle response just revving it seems better IMO though I will know for certain after taking it out.