You are looking at a restored Keihin CR31 smoothbore race carburetor. The carburetor was taken from a 1973 Honda rickman CR750 model. The carburetor was taken completely apart and ultrasonically cleaned and the aluminum bodies were reconditioned to look oem again. All of the seals and jets were replaced with new ones if necessary. The carburetor was than bench synchronized and properly set so all slides move nicely and evenly. But please inspect the pictures for more details to see the condition of the carbs. These carbs will fit many models, and were intended to be performance carbs for honda cb750, Kawasaki z1, z1r, and kz1000 models.