Which Carb is the better one? Kitchen Quiz!!

[scrapmetal]

I was searching in my treasure chest for a Carburetor who fits my XS1B project with a 447 motor,
found a bunch of Mikuni BS38, some of them are from different Motorcycle Brands
who knows something about this Carburetors?
Otherwise, there are more Carbs in the treasure chest, I found a BS34, Honda twin carbs CB/CM400 Hawk, CX500, and at least a carburetor for a Suzuki DR Big, (750/800) BST 33,

What is your experience with Carburetors, not talking about the Brackets, they are easy to change or replace, asking the intake diameter, jets and needles

Cheers

 

[gggGary]

in this pic

1 and 4 look to be XS650 78-79 carbs 2 looks to be 7-75 ish and #3 is not from an XS. Unless you are after serious power gains using 1 and or 4 to build up a good set is prolly the wise course. You would need to use the later 76-79 intake manifolds. They wont work with stock air filter boxes.

 

[grizld1]

Re. alternative carbs, unless they're banked on 120 mm. centers you'll have serious issues. I've banked 33 and 36 mm.Mikuni 4-stroke flat slide pumpers for the XS650, but those have 10 mm. throttle shafts that I could tap and join with a stud and set screws to get the spacing right. The throttle shafts on vacuum carbs have to be thinner, and you'd need to be an ace machinist or know one to deal with the fabrication needed. 1 or 4 would be my choice. (Gary, I think ya meant 74-79 boots, intake angle on all 447 heads was the same).

 

[thuban]

I've been told that the BS38 are one of the best Yamaha made. My bike is very close to stock and the BS38s, set up by the book, work like a charm.
if your gona do a lot of mods to the engine, you'll have to do some trial and error with your carbs anyway.
Thu