manometer / vacuum gauge

[Kiwi_Roy]

Here's to add to Kiwi Roy and Ohio rider = make your own!  (I made this based on someone's earlier post on WG -    )

IIRC everything came from Lowes, though the barb-tite fittings may have to come from the auto parts store.
1/4 plywood about 6'+ long.  Make the PVC expansion chambers 3/4" x12" or bigger - mine are too small and sometimes suck in ATF like they said.  Clear Tygon tubing will heat up at the manifold and slip off the vacuum nipples - put in 6" of automotive vacuum line at the end where it connects to the manifold.  It's nice to have the clear line to see if the ATF is being sucked into the cylinders.  Every thing is strapped to the plywood with zipties.  Fittings in end of expansion chambers are brass barb-tite fittings.  Don't know about T-bodies, but for carbs you can use brake bleeder nipples to connect vacuum lines to the manifold.
[img width=600 height=800]

I think ATF is too thin, the viscosity of engine oil gives it quite a bit of damping so you don't need expansion chambers or restrictors.
Mercury has low viscosity too, more than once I used a manometer in the shop and sent it out the top, although the pressure was within range if it's going too fast it will shoot right out. I would hate to suck mercury into the engine, if it didn't damage something it might vaporize to make a toxic atmosphere.
If you start the bike and it looks like the fluid is going to get sucked out hit the kill switch and make a change to the balance screws or throttles then try again.

Some guys use a drill bit as a gauge to compare one side against the other, that's how I did my Eldorado as it doesn't have anywhere to attach.

[RANDM]

I use a homemade on the R1150R and got around
the worry of anything toxic or harmfull by using
2 Stroke oil in the tube. I any gets sucked in it's
only going to make smoke.

I find it very accurate and easy to use - cost $10Au.

Cheers Maurie.

[Groover]

Here is a link and demonstration on how to use some of devices mentioned. (It's in Italian however)

https://www.youtube.com/watch?v=YMQ7VfjAN3A

I haven't balanced my carbs doing this. I've used a method of starting with the needles set equally, then pulling one cap off at a time and getting the beats and response to be as equally as possible per side, then tweaking a bit when both plugged in to stabilize things. I know this is not correct, maybe I got lucky, but I feel my bike idles well/low and responds well to throttle opening at any range. I'll get one of these units some day to see how close (or far) I really am to where they should be and actually do it right.

[Scud]

I built one myself as described with a piece of wood and plastic tube then clamped it to a support beam on shelf where it "lives" permanently (so it does not become a storage problem).

The only things I can add that have not been suggested so far are:
1) I used air compressor oil - but I would have used two-stroke if I had any at the time.
2) I use a zip-tie when attaching the tubes to the vacuum ports - this not only reduces the risk of one tube falling off, but also reduces the risk of an small air leak, which could lead to a faulty reading.
3) There is almost no risk of the oil being sucked into the engine if the bike is running (even poorly) and if the two tubes are properly connected. Even the low-vacuum side will have SOME vacuum, which will hold the oil back so it will not be drawn into the high-vacuum side. A bit of extra length on the hoses also reduces this risk, with the added benefit of making it easier to connect.

[rbond]

So, to connect the manometer, there is a hose on the outside of each throttle body that I need to remove, put a barb there to put the tubing on? Also the two hoses I just took off need to be plugged? I think they run to the airbox, but am not sure just yet.

[RANDM]

Scud's right,
With a decent length of tubing and zip ties/temperature
resistant connection there's very little chance of anything
going wrong.
Mines on a 1.8m/6ft fence picket, the oil fills the bottom
600mm/2ft and will rise to about 1200mm/4ft @ 3000rpm
as the vacuum increases the suction on the flexible tube.
There's a little pulsing at idle on a big twin, but it's no big
problem.

Maurie.

[Scud]

So, to connect the manometer, there is a hose on the outside of each throttle body that I need to remove, put a barb there to put the tubing on? Also the two hoses I just took off need to be plugged? I think they run to the airbox, but am not sure just yet.

I have not done this on a V7, but I assume it is similar to my V11. The hoses on your throttle bodies that go to the airbox can be left open while you do the balancing. They are probably part of the emissions system, which many people remove completely. You don't need to install any type of barb on the balancing tubes, but as I mentioned above, you can use zip-ties to make the connection nice and snug.

Making your own tool is a good adventure. And if you can do it for $5.00 or less, it gets you a "cheap bastard" Guzzisti merit badge. 

[lucian]

I like the factory method described in my daughters v 50 manual for carburetor balancing. By placing a hand behind the exhaust and feeling the pulse / pressure and adjusting until  they are equal. To my surprise it actually works . One  benefit of dual pipes I suppose.

[sign216]

I "second" the idea of making your own manometer and balancing the TBs yourself.  It's inexpensive and interesting.  A search of the internet should produce a guide on making the device.  I did it a few years ago, but am trouble finding the website I used to build the manometer.

My only warning is to provide a fan blowing over the engine during the balancing.  The engine can overheat when it's just sitting in the garage, running.

[BigDave in PA]

My only warning is to provide a fan blowing over the engine during the balancing.  The engine can overheat when it's just sitting in the garage, running.

+1 I use a fan to cool the engine during the setup. If you balance them with the engine warm it's surprising how soon it will get hot.

[sign216]

+1 I use a fan to cool the engine during the setup. If you balance them with the engine warm it's surprising how soon it will get hot.

Sometimes I have a laptop hooked up with Vehicle Diagnostic Scan Tool (VDST (remember that old program?)) just to watch the engine temperature, and man, it can rise fast.  You won't even realize it at the time.

[ken farr]

Some guys use a drill bit as a gauge to compare one side against the other, that's how I did my Eldorado as it doesn't have anywhere to attach.

Hey Kiwi, could you expand on this for me, I haven't heard this before....

kjf

[SED]

Hey Kiwi, could you expand on this for me, I haven't heard this before....

kjf

Hey Ken,

The first goal is to make both slides exactly the same height when the throttle is open.  Get a drill bit or I use a small piece of perfectly round tubing about 1/2" diameter.  Open the throttle until the tube just fits under the throttle slide and lock the twist grip.  I move the tube in an out of the throat of the carb until I get a feel for the clearance on the right carb, then go to the left carb and check that side.  Adjust the cable lengths until both sides feel the same - then reset the twist grip and double or triple check.  (I found the OEM plastic twist grips from the early '80s were different every time they closed and opened so replaced them.) 

The second goal is to make the slides exactly the same height on the idle stops.  Loosen the twist grip and let the slides fall to their stops (idle).  Check the idle balance by inserting a 4-6" piece of bamboo skewer or chop stick into each carb throat so that the inside end is under the edge of the slide.  Marking the skewer at the edge of the carb mouth will tell you they are inserted the same amount.  Watch the ends of the skewers and crack open the throttle with the twist grip - the skewer that dips first is on the side with the lower idle setting.  Screw in the idle stop screw until both skewers dip at once.  Triple check.

I set the carbs this way then checked with the manometer and they were surprisingly close.

Shawn
 

[RANDM]

My only warning is to provide a fan blowing over the engine during the balancing.  The engine can overheat when it's just sitting in the garage, running.

I used one fan for each jug on the BMW - think I'd do the same
On a Goose just to be sure : )

Maurie.

[ohiorider]

+1 I use a fan to cool the engine during the setup. If you balance them with the engine warm it's surprising how soon it will get hot.

I try to do the balance in minimum time, but I agree, it would be nice to have a good fan system.  My dealer in Greensburg PA, 30 years ago, had a fan setup made up of two squirrel cage fans that were spaced approx. the same width apart as were the airhead cylinders.  These fans had adjustable vents on them, so each could be directed at the right and left cylinders.

Neat setup.

[Tony/CT]

It looks like the Carbtune can be purchased and shipped for 50 pounds which is about $75.00 U.S. The Carbmate can be purchased and shipped in the U.S. for $103.00. The Carbtune looks to be a good buy.

[Antietam Classic Cycle]

It looks like the Carbtune can be purchased and shipped for 50 pounds which is about $75.00 U.S. The Carbmate can be purchased and shipped in the U.S. for $103.00. The Carbtune looks to be a good buy.

The Morgan Carbtune is £64 with shipping, currently just over $95. Worth every penny IMO.

[sign216]

The Morgan Carbtune is �64 with shipping, currently just over $95. Worth every penny IMO.

I have not doubt the tools are available, but there's something to making it all yourself with just some tubing and a pine board for next to zero dollars.

[Tony/CT]

My father in law, hearing I was  considering purchasing a manometer brought his over, that he uses on his furnace, a Pyle PDMM01. I haven't opened up the directions yet, but does anyone know if I can use this to balance the carbs on my Ambassador and BMW airheads?

[Wayne Orwig]

My father in law, hearing I was  considering purchasing a manometer brought his over, that he uses on his furnace, a Pyle PDMM01. I haven't opened up the directions yet, but does anyone know if I can use this to balance the carbs on my Ambassador and BMW airheads?

The info I found, only mentioned pressure, not vacuum, so that may be an issue.
It looks like it will do differential PRESSURE. So it might work.
It also may not have much damping, so the numbers may be all over the place. But it does say it has an average function, so it may work well.

Worth a try, but I wouldn't be surprised to find that you have a screen full of dancing numbers that don't mean as much as a simple column of oil in a tube.

[Seagondollar]

I've had an idea for an electronic manometer that would remain on the bike, running when the engine is.  How many people would be interested in it and would it be worth something like $75?

[Tony/CT]

The guys on the BMW Airhead site are extolling the virtues of the Grok Harmonizer. Anyone hear of it?

[Seagondollar]

Geodoc posted it on the first page.  What I want to build is something smaller like this that stays on the bike and you see what's going on when you are riding.

[Kiwi_Roy]

I assume your idea is based on one of the inexpensive DP cells available, that will work.