Vacuum Guage and Carb Tuning

[khardrunner14]

Is it possible/workable to sync the carbs with a standard vacuum guage assuming I get the correct adapters? Or, do I have to buy a carb sync tool?

[Steve]

It might be possible to do it with one guage, but you would need to do a lot of prep work.

You would still need to have fittings on each intake, with a piece of tubing going to a manifold with individual valves for each throat. You would have to get a reading on #3 (the master carb for CV systems), then turn that one off, turn on #2, compare the reading. Adjust as necessary, check reading on #3 again, then go back to #2 to make sure. Then check #1 the same way, then #4. With all the switching on and off of all the valves, I think you would find it much easier to just get a rack of 4 gauges and check them all at once. Cost isn't really all that bad, and the convenience is definitely worth it.


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[Nessism]

I read about people doing it using a couple of valves from an aquarium to open flow from each carb with the twist of a knob. Best to build a plentum out of PVC also and add line restrictors as well to damp the needle fluctuations.

[KEITH KRAUSE]

Motion Pro makes a good synch tool that works as well as the operator. About $40 last I looked. I've used one for many years.

[khardrunner14]

I found the pro motion economy tuner for like 65 bucks (59 at the cheapest). I guess I'll have to go that direction.

[bexabarr]

I read about people doing it using a couple of valves from an aquarium to open flow from each carb with the twist of a knob. Best to build a plentum out of PVC also and add line restrictors as well to damp the needle fluctuations.

http://www.xs11.com/forum/showthread.php?postid=4652#post4652

[Nessism]

http://www.xs11.com/forum/showthread...=4652#post4652

That's the one! \\/

I made two plenums, one for each cylinder on my 450. Even still, the needles fluctuated wildly. Some restricters in the tubes would go a long way to reduce this tendance I think (my Motion Pro mercury sync tool has restricters which seem to help).

[bexabarr]

That's the one! \\/

I made two plenums, one for each cylinder on my 450. Even still, the needles fluctuated wildly. Some restricters in the tubes would go a long way to reduce this tendance I think (my Motion Pro mercury sync tool has restricters which seem to help).

really? so it didn't work out too well? because back in the day I wanted to do the same, however I ended up making a carb tune out of some clear tubes... it worked well. I experimented with some liquids but ended up using small ball bearings (two for each tube worked well)... I took some pics just now but I can't find my usb cable. I'll post it when I find it.

[Nessism]

really? so it didn't work out too well? because back in the day I wanted to do the same, however I ended up making a carb tune out of some clear tubes... it worked well. I experimented with some liquids but ended up using small ball bearings (two for each tube worked well)... I took some pics just now but I can't find my usb cable. I'll post it when I find it.

The gauges work fine BUT they would be better with some restrictors in the tubes so the needles would be more steady. The Motion Pro carb tool comes with restrictors and I think they would be a good idea for a home built sync tool as well.

[bexabarr]

Lol you got me thinking on a way of restricting my device... I did a little research and found some guy who restricted their mercury gauge with cigarette filters. I may try it with some rolling tobacco filters when I re-sync mine (very soon).

[Nessism]

Lol you got me thinking on a way of restricting my device... I did a little research and found some guy who restricted their mercury gauge with cigarette filters. I may try it with some rolling tobacco filters when I re-sync mine (very soon).

An appropriately sized chunk of wood dowl with a small hole drilled down the middle stuffed up into the tubing will work. The Motion Pro restricters are just little plastic plugs with a hole.