Manometer idea for carb sync's

pidaster wrote:

fixer5000 wrote:

you can make your own synchroniser using 4 0-30 vacuum gauges, 4 elbows and 4 flow control type dampners. like this one i made below. its crude but it works great..steve

How much did this setup cost you?

this setups about 20 yrs old but after checking on mcmaster car i think anyone could build this for about 100 bucks today. this is all heavy duty quality industrial stuff and will last a lifetime....steve

I'm all for building your own, but there are a few fundamentals to follow.

There needs to be a pinhole size restriction as close to the manifold port as possible. This is to isolate the test apparatus from affecting the vacuum inside the manifold. It should be at the very beginning of the tubing. As I mentioned earlier, it needs to be adjustable in order to make all four test channels the same. On store bought ones, you just wiggle a needle in the orifice.

If the restrictor (which also performs dampening), is placed at the gauge-end of the tubing, it doesn't shield the manifold from the effects of the tubing capacitance. The reading will be off because the apparatus is affecting the actual vacuum inside the manifold.

Intuitively, it would seem that if everything was identical, none of these concerns would make a difference. However, in practice, making all four channels identical are impossible. The tubing, alone, will vary greatly in diameter and wall ridgidity. That's enough to be off by up to 2 inches of mercury.

Last night I decided to build the $1.55 carb sync tool for two cylinders, (cost me $2.28). I bought 12 ft of 1/4" od hose. The id barely fit the vac ports on the 650, so if you try this buy a hose with maybe a 7/32" id.

When I rebuilt and synced the carbs last year I used a homemade device below.


I took the readings from each carb and averaged them, then I set each carb to the average. It seemed to run well and idle smooth.

Last night I built the 1.55 sync tool.



I checked the carbs, which showed them off a bit. I adjusted 1-4 and 2-3, then checked 1-3 and 1-4 and made some minor adjustments to get them even. The result is a smoother idle and it seems to pick up and run better. I'm happy!

My transmission fluid is really jumpy and gets air mixed in with it. What do I do to solve this issue?

Never mind. Filled lines with about three feet of fluid. Worked great.
Motor purrrrrrs now. I was amazed how far they were off. The first few times per carb, I had to immediately shut the engine off before it sucked it up. Carbs 1&2 were the worst off.

Post edited by: pidaster, at: 2006/05/24 22:32

Yes mine acted like that too. I wound up with about 40 inches of fluid in each side. This cheap hose and stick is more accurate than the rig I made in the top picture.

Are we better off using a larger or a smaller ID tube when building the "sync-a-matic 2000".

Say use 7/16" ID tube on the actual device, connected, via reducers, to say 1/4" ID for the hook-up to the manifold spigots.

Logic suggests the fluid might bounce less in a larger tube?

Any thoughts?

Not sure about the size but I can warn you of this. After siphoning about three feet of fluid per line for a total of six feet, everytime I burped thereafter it tasted like Mercon V transmission fluid.:sick: That's after I ate my dinner too.:woohoo:

BARNEYHYPHEN wrote:

Are we better off using a larger or a smaller ID tube when building the "sync-a-matic 2000".

Say use 7/16" ID tube on the actual device, connected, via reducers, to say 1/4" ID for the hook-up to the manifold spigots.

Logic suggests the fluid might bounce less in a larger tube?

Any thoughts?

I guess that would work. Maybe a heavier fluid would do the same thing. What "weight" is tranny fluid? Maybe straight 30w would dampen it. I used red tranny fluid as it was easy to see.

I would think tranny fluid falls in the 10w-20w area but I could very well be wrong.

JMKZHI wrote:

My bike was balanced using the home made manometer. I was originally going to use the dual-tubing setup but realized that it would be too fiddly & cumbersome trying to do 2 carbs at a time, so I made the 4 carb gizmo

1/4" clear tubing, clamps & caps; some larger sized clamps; 1/4" black watering system fittings w barbed ends (2-90s & 2-Tees); 1x4 board, metal yardstick (I couldn't locate a meterstick); 2-cycle oil.

JMK.

Couldn't you just leave off the tee connection at the bottom and have all four tubes sitting in a large container of oil or something? Then they wouldn't be fighting one another at all.

It would also make it open to the atmosphere so you shouldn't need to worry about calibrating it first.

Whachall think?

I don't know... maybe.

Little B wrote:

JMKZHI wrote:

My bike was balanced using the home made manometer. I was originally going to use the dual-tubing setup but realized that it would be too fiddly & cumbersome trying to do 2 carbs at a time, so I made the 4 carb gizmo

1/4" clear tubing, clamps & caps; some larger sized clamps; 1/4" black watering system fittings w barbed ends (2-90s & 2-Tees); 1x4 board, metal yardstick (I couldn't locate a meterstick); 2-cycle oil.

JMK.

Couldn't you just leave off the tee connection at the bottom and have all four tubes sitting in a large container of oil or something? Then they wouldn't be fighting one another at all.

It would also make it open to the atmosphere so you shouldn't need to worry about calibrating it first.

Whachall think?

The problem with that is that the manometer would have to be super tall.

A 2-foot mercury manometer would have to be replaced by a 20-foot water manometer. Oil would have to be even taller.

Post edited by: loudhvx, at: 2008/01/20 22:23