Found a good reference at
http://www.motorcyclecarbs.com/Keihin_FCR_Spigot_Adapter_Appl_W53.cfm
Ducati [single carb]
44.5mm OD
39mm ID
Intake Manifold Boots: Tube Type 44mm
To suit carburetors or intakes with an external fitting diameter of 44mm.
Overall length 32.9mm
Application: Dellorto PHF /PHBE
Sold individually.
Lots of info:
http://www.motorcyclecarbs.com/Intake_Manifolds_C1466.cfm
Top > Carburetors and Carburetor Parts > Intake > Intake Manifolds > What to do when you cant find a Carb Holder.
Carb Holders or Intake Manifold Boots
Carb holders, (carburetors manifold boots) mount a carburetor to an engine. These holders are available in either a flange, or tube method in most cases. Details of these mounting types create some variables.
Flange Mount:
Two bolt. Used mostly on 4 stroke applications.
Four or more bolt. Used mostly on 2 stroke applications to feed reed valve cages.
Tube Mount:
Used mostly on multi cylinder 4 stroke applications.
When you need to replace an original Carb holder you may find an exact replacement unavailable. In this case maybe the following info may be found useful.
Original replacements are unavailable.
Aftermarket replacements for that application are unavailable.
So how to solve this.
Lets look at more facts:
Permanently repairing carb holders not possible.
An OD of aluminum goes into an ID of rubber.
A two bolt flange bolts to the head.
There are literally hundreds of available intake manifold boots.
Aluminum press on sleeves can be machined to change the OD of your carbs.
An aluminum flange can be made to allow a different bolt pattern to be used on your head.
Make a 1/4" thick aluminum ring Bolt the disc to the head. Mount the new manifold to the ring. This is not the best solution if you retain your stock air box as you may not be able to mount the carbs to the box.
Note that a longer intake tract promotes torque at the expence of high rpm horsepower.
Flanges of different hole spacings can be machined to be slotted so they will mount.
Your carbs if the same as another model in general maybe similar enough that the other model may only be slightly different. Then if there is a part number difference the other bikes holder may work with slight modification.
Carbs for a year newer or later if made, would work for the machine but may use different manifolds. However you could change carbs to that year.
We could put performance carbs on there that use different manifolds that ARE available.
You can usually clamp down a manifold boot 2mm too large tight enough not to leak.
You can ususally press carbs into a 2mm too small manifold boot because of the rubbers flexibility if fresh.
However it is best to provide the mounting dimensions. Specifically the OD of the carb on the engine side, and the center to center distance between the mounting bolts we may be able to find you something to work with.
