Vacuum guage on a Ducati V-twin...
 

As far as I am aware, my Ducati ST2 has the two throttle bodies side-by-side botled together and sat between the 2 cylinders.

However, each throttle body then feeds into an individual inlet manifold per cylinder.

Could I run a vacuum guage off of just on inlet?

Would it be far to 'bouncy' for an accurate reading?

Could I take a feed from each inlet manifold and join them with a 'Y' style connector, or would this ruin the vacuum in the cylinders?

I'm confused....

A 3mm feed to a tee will be fine. Many bikes have these kind of connections already, when vacuum operated accessories are present, to balance the vacuum pulses for a cleaner operation.

Being a twin, you may need to add an accumulator to keep the gauge from bouncing. Something about the size of a pocket pack of gum might do it.

Whats an accumulator?
Where would I find one?

It'll be a can of sorts that both cylinders pull vacuum on. The volume will help dampen the pulses of vacuum.

13mm I.d. Pvc with acap at each end to seal it. 50 or 60 millimeter long inside? Thread each end with hose barbs.

i fell retarded, cause you guys lost me. what does this vacuum gauge do?

Smart answer - A vacuum gauge is an instrument used to define a numeric value to the negative pressure in an enclosure or duct.

The answer you're looking for - A fairly primitive way to gauge fuel economy by gauging manifold vacuum, or in this case, port vacuum which can be used to roughly define engine load. This data then enables the operator to make changes based on the information given, such as change gears increase or decrease throttle to maintain desirable load, which translates to better fuel economy.

so basically, its works about the same as a fuel/air ratio meter, but through a different process?

im not trying to sound like an idiot here, i just didnt know what it was.

I believe its detailed in the 101 mods.

I have one fitted to my 1990 Eunos/Miata (purely because it is too old for any aftermarket data programs to run on).
It lets me 'see' the pressure in the intlet manifold between the throttle body and the cylinders.
It basically regulates my right foot and helps me accelerate or maintain speed more effeciently.
Its amazing how often at most speeds I can back off the gas a tiny bit, yet still maintain the same speed?!
I'm sure someone will correct me if I'm wrong, but if I'm able to restrict how open the throttle butterfly is, based on what I can see the vacuum gauge doing, then I can run the motor a little more 'lean'.

Cheers bud.

Are you describing a known product here, or is this the instructions for something that can be self fabricated?