$1.55 Carb Synchronizer

[Bill]

Fellow XSives -

For all the folks who have felt that they just couldn't afford a carb synch tool, I just came across an interesting DIY project.

$1.55 Carb Synchronizer
It's the ultimate in low tech and designed to balance two carbs. However, it could be used on four carbs if done in three pairs, using the following sequence:

Balance carb #1 to #2, #3 to #4, then #2 to #3.

Can't beat the price! Any thoughts?

[Mike Hart]

the $3.10 synchronizer

build two?

[Bill]

Re: the $3.10 synchronizer

Mike Hart wrote:

the $3.10 synchronizer...build two?

I thought about that, too, until I looked closely. It's just one continuous u-shaped tube with fluid (2 stroke oil) in the bottom. Here's how it works...

• Hook the tube between a pair of carbs
• The fluid is pulled toward the one with the higher suction
• The fluid stays in the tube because it's being pulled from both ends

Since the tool isn't calibrated, it can only indicate balance between two sources. With two you could balance your left and right pairs (1&2, 3&4) at the same time, but you'd still have to balance left to right afterward. In that way it's similar to the Pre-synchronizing Carbs tip.

[Mike Hart]

still a great idea to tweak on - nice find.

Hmm.. 4 long tubes glued to a sealed container of
heavy oil?

And if you did suck some fluid in, it's only oil,
not mercury!

[Bill]

Re: $3.10 Carb Synchronizer?

Mike Hart wrote:

Hmm.. 4 long tubes glued to a sealed container of heavy oil?

Now you REALLY have me thinking. Keeping with the "loop concept", what about just using a little 4-way "X" manifold? Seems that should work because all four vaccuum sources would be pulling against each other. Now I HAVE to prototype that idea! I wonder how small it could be and still work effectively?

[skids]

Heavy oil. Hmmm, why not use water? Cheaper, disposable, non messy.

[Mike Hart]

True, water is heavier than oil. Don't think I'd want water
sucked into the carbs any more than mercury. Oil is easier
to see in the tubes? ok, colored water...

[Bill]

Perhaps colored alcohol (Ethyl or Isopropyl). Not messy, yet burns readily. A little food coloring in a bottle of dry gas would do the trick!

[irb9494]

I read somewhere that people who use these homemade sync gauges also use a glycol solution such as anti-freeze. I guess it provides the color you need as well an not causing too much damage if it gets into the carbs. Just an idea.

[skids]

Red oil is typically used in manometers becuase it is temperature-stable. Water will not hurt cylinders. I was told that it is one way to blow carbon out of the combustion chamber.

[skids]

Propyline Glycol is a type of sugar, isn't it? I wouldn't put that in MY engine!

[Ken Talbot]

Hmm, I just can't quite visualize pulling this off with a 'four long tubes' scenario using coloured water for the indicator fluid. IIRC from Miss Taylor's eighth grade science class, a complete vacuum would draw up a column of water approx 32 feet high, so maybe you could get away with only 20 foot columns as long as you were careful not to slam off the throttle too quickly. I dunno about you, but I don't have a 10 or 15 foot deep pit next to where I do my tune-up work in the carport.

Ken Talbot

[Mike Hart]

hmm the orig tip used oil...

w/ equalization factor...



What liquid is heavy but not toxic?

[Ken Talbot]

The original tip also seemed to have two tubes pulling against each other rather than drawing from a reservoir. I still haven't got my mind around that concept....

[Bill]

Ken Talbot wrote:

Hmm, I just can't quite visualize pulling this off with a 'four long tubes' scenario using coloured water for the indicator fluid. IIRC from Miss Taylor's eighth grade science class, a complete vacuum would draw up a column of water approx 32 feet high, so maybe you could get away with only 20 foot columns as long as you were careful not to slam off the throttle too quickly.

I don't think the reservoir is the answer.
Picture this:

• In the original example, 2 carbs are connected by a single, continuous tube
• Vaccuum from each carb acts on the fluid from both sides
• If the carbs are in balance (i.e. equal vaccum), the fluid remains centered at the bottom of the loop
• The tube length only has to allow for the difference between the carbs.
• To me, it follows that connecting 4 carbs together by use of an "X" or "+" shaped manifold should work the same way.

Does that make sense?