20mm Carb info?

I need some help finding out what carb I have
I bought 2 carbs off of e-bay for 26$ (shipped)!!!
they are supposed to be 16mm, but I measured the opening and get 20mm
I e-mailed the guy I got them from, but still haven't got a reply
this link is the same set,
http://cgi.ebay.com/ebaymotors/2-CA...006QQitemZ160226751375QQrdZ1QQsspagenameZWDVW
when they came there were 2 hoses connected...
one was at the top beside the slide (which I assume is fuel inlet), the other is coming off the bottom of bowl, the use of, I'm not sure
there is also a petcock on the side of the bowl, which I think is for draining
I also am going to make up a thumb-shifter type deal for the cable actuated choke
if anyone can help with any of my questions, or tell me where to find info I would be very greatful

the markings on the side say 'Sheng Wey' with a large K in the casting
the rest of the markings are printed:
TBT125 1J07
0310 0721
there is also a large 'K' at the front of the above numbers, and the same size '11', at the end
pics below

 

thread title error

could a mod please edit the title to show 20mm please
...brain fart on my end :lol:

 

From the pictures I can tell you the hose on top is for the throttle cable and the one on the float bowl is the fuel inlet with a built in shutoff valve.
The small outlet on the float bowl is probably a float bowel over flow outlet, you should have a hose on that drops down below the bottom bracket to dump fuel over flows in the float bowl

 

Carb size is usually measured where the venturi is smallest.

http://en.wikipedia.org/wiki/Carburetor

Read that

 

You could measure the inside of the manifold side (in inches) then use the attached conversion site to covert to millimeters.
http://www.sciencemadesimple.com/conversions.html

 

Its measured at the narrowest part of the venturi, not an easy place to measure without an engineers inside micrometer.

Do you understand the venturi effect? Its how carburettors function.

 

Nice looking carbs, ye that other pipe is definetely a fuel overflow to stop it flooding, I've seen them before on pocket bikes

 

Where is this going to? A Happy Time?

I would imagine even a carb bigger than 20 would still work,cause like in cars,you can get a bigger carb than what the engine needs,which is usually what gearheads do.

 

LF, yes, it's going on a 70cc livefast engine
already made a plate to be welded on a steel manifold so we can bolt it up
hope to get it welded, mounted and tested tomorrow
I will let everyone know if it works or not
seemed like a cheap enough experiment

 

Any luck with the carbs? Look forward to hearing the results, they look really smart too

 

do you have a tuned pipe? I have to know how the combo of a performance carb and a tuned pipe is.