Hello folks,

Pictured above is a remarkable little tool, that you're going to love using, (or smashing against the wall) LOL !

This device is specifically meant for the use of synchronizing the throttle-positions, typically at idle speeds, of multiple carburetor, or multiple throttle-body equipped, cars & motorcycles alike...

Unlike regular manometers, the graduations found on the gauge are not specific for any measurement, other than being a reference-point for your adjusting of the throttles, as per OEM recommended procedures, & operating RPM's. Up to 4-throttles can be synchronized simultaneously.

Regretfully, these new gauges are the environmentally friendly type, where the original fluid used, namely Mercury, has been substituted for a blue, petroleum-oil-based fluid.

With the Mercury manometer, all 4 level indicator tubes shared the common well of the Mercury liquid, & no gauge calibration was required. You simply warmed your machine up, followed the directions as per the manual for testing / adjusting, hooked the rubber hoses on to the carburetor air-piston diaphragm access-port, & adjusted the throttle screws gently & evenly where needed, to bring the liquid in the tubes to the same level / height. Some early motorcycle manuals where the engine was air / oil - cooled, allowed the 2-middle columns to be slightly lower than the outer tubes, since the inner cylinders had less surface area getting cooled, & needed a subtly richer running mixture.

With this newer gauge set, a plastic multi-port manifold is provided, so as to bring all 4-rubber-boses feeding vacuum from a common source, namely cylinder 1, once plugged on to the air-piston diaphragm access port. Once fastened, the warmed-up engine is started, & the height of the fluid is equalized via adjusting screws located near the bottom of the measuring tubes, & now the calibrated gauge is ready to use.

As before, each rubber vacuum-hose is fitted to an air-piston diaphragm port, or throttle-body provision, the warm engine started, & adjustment of the throttle screws is made until all the fluid levels in the metering columns is equal. - ( Or as specified ).

Some issues found with this tool in the past, has namely been air-bubbles appearing in the columns, giving uncertain readings, & of course, you have to start all over again, once the tool has been bled-free of air...This was the main issue with the 1st-generation of new environmentally friendly fluids, where a more anti-freeze based fluid was used.

I have only just rebuilt my gauge-set with an O/haul kit, & new oil-based fluid, & so cannot just yet comment on the results of the new fluid type. I had been using plane distilled water for a number of years with good success, but once I saw the new oil-based fluid type available, I thought I'd try it out. ( Easier to see blue fluid, than clear water !!! The original blue fluid with my gauge-set evaporated within 12-months. I've been using distilled water for the last 8-years LOL ).

You can expect dramatic improvements in power, throttle-response, & fuel economy when using this gauge-set, since all the throttles are equalized in their positions. This means evenly breathed air & fuel quantities for each cylinder. Awesome.

This gauge-set is also readily adaptable for cars too, where multiple carbs are used or even IR systems incorporated, though another gauge set may be required here.

Cool stuff,

Rastus