This 26mm carburetor with manual choke lever is most commonly used for (but not limited to) 125cc to 250cc ATVs and dirt bikes. Also very commonly used for many models of golf carts and other models of Go karts / buggies and some scooters.
Manifold: 25.7mm
Breather Inner Diameter: 34.7mm
Breather Outer Diameter: 39.8mm
Bolt Mount (centre to centre): 48mm