Real 20mm Carburetors vs fakes - with pictures
Mar 23, 2015 7:52:24 GMT -5
90GTVert, moofus02, and 7 more like this
Post by humanshield on Mar 23, 2015 7:52:24 GMT -5
I touched on this once before in another thread but due to a very large number of people buying fake 20mm carburetors, I wanted to make a thread dedicated to this. I got burned myself and this might save others from getting duped.
There are a LOT of vendors selling 18mm carburetors as "20mm" carburetors. Especially on ebay.
What they are doing it taking an 18mm carburetor (dirt cheap from china in bulk), and machining a very small portion of the outlet flange on the intake manifold side so that the last 1/2 inch or so is 20mm, but NOT the entire venturi going through the carburetor and the BUTTERFLY size is still 18mm.
Doing this does NOT increase the performance of the carburetor and does not increase the volume of air that can pass through the carburetor. You will still have an 18mm carburetor. Imo, it's downright false advertising.
Here are some photos to help identify fake 20mm carburetors....
In this first photo you can see the ridge left from the machining where it stops.
As you can see, after the machining, the bore size is larger ONLY up to the machining ridge.
All they did is bore a hole into the barrel that is 2mm larger than the original 18mm.
But because the machining stops before the butterfly valve and because the rest of the venturi
is still 18mm, there is no performance gain. You still have an 18mm carburetor.
Here is an angular view of another fake 20mm carburetor.
Again you can see where the machining stops.
To try and conceal the machining, some carbs are machined all the way right up to the butterfly valve
making it a bit harder to tell it was simply machined. You need to verify that the carb in fact has a 20mm
butterfly before purchase.
Finally, here is a photo of a TRUE 20mm carburetor....
There is no machining and the seller will verify that the butterfly valve is in fact 20mm.
(The butterfly valve is the brass plate with two screws)
This carburetor can provide improved air flow volume for Big Bore Kit motors.
There are a LOT of vendors selling 18mm carburetors as "20mm" carburetors. Especially on ebay.
What they are doing it taking an 18mm carburetor (dirt cheap from china in bulk), and machining a very small portion of the outlet flange on the intake manifold side so that the last 1/2 inch or so is 20mm, but NOT the entire venturi going through the carburetor and the BUTTERFLY size is still 18mm.
Doing this does NOT increase the performance of the carburetor and does not increase the volume of air that can pass through the carburetor. You will still have an 18mm carburetor. Imo, it's downright false advertising.
Here are some photos to help identify fake 20mm carburetors....
In this first photo you can see the ridge left from the machining where it stops.
As you can see, after the machining, the bore size is larger ONLY up to the machining ridge.
All they did is bore a hole into the barrel that is 2mm larger than the original 18mm.
But because the machining stops before the butterfly valve and because the rest of the venturi
is still 18mm, there is no performance gain. You still have an 18mm carburetor.
Here is an angular view of another fake 20mm carburetor.
Again you can see where the machining stops.
To try and conceal the machining, some carbs are machined all the way right up to the butterfly valve
making it a bit harder to tell it was simply machined. You need to verify that the carb in fact has a 20mm
butterfly before purchase.
Finally, here is a photo of a TRUE 20mm carburetor....
There is no machining and the seller will verify that the butterfly valve is in fact 20mm.
(The butterfly valve is the brass plate with two screws)
This carburetor can provide improved air flow volume for Big Bore Kit motors.
Ebay has saved my butt on these things. Both sellers I bought from turned out to be no good even though they talked a good game before purchase. Both then tried to screw me after the sale and ignore my requests for return.