Carburetor measuring  By  triker (Read 337 times)

I juts got a 20mm carb. I opened up the bowl to see what size jets are in it. They are mystery jets as neither one is marked. But that is not why I'm typing this. I then measured the outlet of the carb to determine if it was a 20mm. I measured right at the end. and it measured 19.77mm. Ok so it's a little small. now this is where it gets interesting. I use a telescoping gauge to measure deeper down by the throttle plate, and at this point it measures 18.45mm. I get out my notebook to write these two measurements down. I notice that in the list of carb measurements I had measured an 18mm carb and a 19mm carb. these measurements are as follows:

18mm carb at the lip:18.52mm, at the throttle plate: 18.45mm

19mm carb at the lip: 19.25mm, at the throttle plate: 18.45mm

20mm carb at the lip: 19.77mm, at the throttle plate: 18.45mm

My 24mm fuel injection throttle body measures 23.95mm at the lip and throttle plate.

Now I'm wondering why I have 3 different size carbs, but they all have the same size throttle plate. Any one care to enlighten me?

Roy