Specifically Sizes and ID Numbers
I have two Express carbs laying around and I got them both out to look them over. I also looked at my Shop Manuals for both NC50 and the NU50 Urban.
The carb spec'd out in the manual for the Urban is a PA 13E, the other manual for an NC50 Express had no ID numbers available. The second carb ID number is PA 25A
The venturi size of both carbs measured the same @ 12mm. The mounting flanges have different bore sizes @ 16.5mm and 13.78mm for the Urban carb.
The filter mounts are the same @ 25mm.
I did not open them up to inspect the jet sizes.
