Wildguzzi.com
General Category => General Discussion => Topic started by: rbond on December 15, 2015, 08:50:12 AM
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Where and what type of gauges do I need to balance the throttle bodies for my V7C?
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I have this one: http://www.carbtune.com/ . Super easy to use, very accurate.
(http://www.carbtune.co.uk/Images/SSL11411SC.jpg)
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I have this one: http://www.carbtune.com/ . Super easy to use, very accurate.
(http://www.carbtune.co.uk/Images/SSL11411SC.jpg)
I'll second that notion.
Steve.
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When the mercury went bad in my carb sticks, I started using an electronic Twinmax. I hate the thing, but it gets me by. Avoid the Twinmax.
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yep carbtune all the way
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When the mercury went bad in my carb sticks, I started using an electronic Twinmax. I hate the thing, but it gets me by. Avoid the Twinmax.
Love my antique carb stick. I've got a quart jar of mercury in the shop. Stop by and I'll fill up your old sticks for you.
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10 ft of 1/4" tube on a stick
a little bit of engine oil
The most accurate gauge you can buy make
Seriously a stick about 4ft long
Tape the tube to it in a "U" shape with one end about 2 ft longer than the other
Suck some oil into the tube until it fills the bottom 2 feet of the "U" section.
To attach it to the throttle bodies you will need a couple of nipples, you can make these from grease
nipples with the tip filed off the thread to let the spring and ball out.
You will need to wire the tube to the nipples or it will let go when it's hot or use rubber for the last few inches.
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i use the harmonizer vacuum gauge....great tool... no mercury so you can take the bike for a spin and see what the carbs are doing under different conditions. i know what ya'll are going to say.
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i use the harmonizer vacuum gauge....great tool... no mercury so you can take the bike for a spin and see what the carbs are doing under different conditions. i know what ya'll are going to say.
No you don't, I think it's a great idea to check it under load, there are lot's of small differential pressure transducers available, I think the harmonizer works with one.
If you want to measure the difference between two pressures there is no better way to do it than a differential pressure gauge like a DP cell or manometer.
I think the carb sticks are more like 4 separate gauges, correct me if I'm wrong.
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you are correct..
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Avoid the Twinmax.
I have one, too. Not impressed.
Rich A
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I'll second that notion.
Steve.
Thirded, I've been using carbtune gauge for years on my Ducatis and they run as sweet as. Used it on the Guzzi and that too ran sweet as - until the pistons hit the exhaust valves... :rolleyes:
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10 ft of 1/4" tube on a stick
a little bit of engine oil
The most accurate gauge you can buy make
Love my antique carb stick. I've got a quart jar of mercury in the shop. Stop by and I'll fill up your old sticks for you.
One of the best things about the Morgan Carbtune is that you can lay it in a drawer, toolbox, etc. without it leaking out oil or toxic mercury.
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Love my antique carb stick. I've got a quart jar of mercury in the shop. Stop by and I'll fill up your old sticks for you.
I just may take you up on that. :smiley: I loaned my antique :rolleyes: carb stix out one time..bad idea.. and it came back about half empty. I thought, "oh, no problem, I'll just get some more mercury." Not.
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10 ft of 1/4" tube on a stick
a little bit of engine oil
The most accurate gauge you can buy make
Seriously a stick about 4ft long
Tape the tube to it in a "U" shape with one end about 2 ft longer than the other
Suck some oil into the tube until it fills the bottom 2 feet of the "U" section.
To attach it to the throttle bodies you will need a couple of nipples, you can make these from grease
nipples with the tip filed off the thread to let the spring and ball out.
You will need to wire the tube to the nipples or it will let go when it's hot or use rubber for the last few inches. EDIT - sorry, KW Roy, didn't see that you'd already covered this.
Here's the write up I found years ago on a BMW site for making the fluid manometer. There's a few caveats when using one of these:
- If your TBs are waaay out of balance, the one producing the most vacuum will suck all the ATF fluid into that cylinder. Smoke aplenty!
- If the TB vacuum ports get really warm, the tubing may soften and fall off one side with the same result. Smoke
To cure that problem, I found some plastic connectors that permitted me to attach a few inches of tubing that was less affected by temps, and didn't want to fall off a vacuum port.
- Others have built these home made manometers and implemented small reservoirs near the top of the instrument to capture fluid if it gets sucked up one hose toward that cylinder.
Having said that, I cannot imagine any costly manometer or other instrument being more accurate, unless you want to measure the specific vacuum at each port. Which in our case isn't of much value, since what you're attempting to do is set the vacuum on right and left to be the same.
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Written by Hugh Kenny
Friday, 01 March 2002
Since joining the Airheads shortly after purchasing my first-ever Beemer in October of 2001, I've found the AirList to be an invaluable source of information and direct feedback as I learn my way around my new 1984 R100RS. One of the first things I do when acquainting myself with a new mount is a basic tune-up. Lurking on the Airlist provided a bunch of helpful tips to supplement (and correct) the tune-up info in the Haynes and Clymer manuals.
One of the slickest tune-up tips I came across was Tom Rowe's mention of a ridiculously cheap and easy-to-build differential manometer (vacuum gauge) for balancing carburetors on vacuum port equipped Boxers. I'd read about the Twin-Max (aprx. $80) and have used the $40 CarbStix on my 4-cylinder Hondas, but for less than $4, I was able to build a twin carb synchronizer that is 16 times more sensitive than my mercury vacuum gauges and can be assembled from common materials available at almost any hardware store. I built it and my R100RS loved it - it really smoothed out some bands of footpeg/bar/mirror vibration that the bike had, even after using the CarbStix.
I posted a 'Thank You' note for the idea on the AirList after I tried it and got even more valuable feedback from Jay Carpenter and a request from John "Beetle" Mailleue, ABC# 5657 to write a tech article for the AirMail. After spending some more time in the garage incorporating Jay Carpenter's ideas, I figured I'd go ahead and write-up a description of how to build and use the $4 Carb Synchronizer, because it REALLY works. Super cheap, super accurate, super easy to build and super easy to use - CLASSIC Airhead technology!
Credit for the original idea has to go to Marty Ignazito of the powered-parachute crowd, he came up with the idea to balance the twin Bings on a two-stroke Rotax and his original write-up is at www.powerchutes.com/manometer.asp. If you try this idea and like it, send Marty a thank-you e-mail at mdipe@mcleodusa.net .
Here's the Materials List for the $4 Carb Synchronizer Tool:
• 20 feet of clear plastic (vinyl) tubing - inside diameter big enough to slip on the vacuum nipple of your carb (3/16" i.d. worked for my bike, but it's tight, maybe 1/4" i.d. might be better). 15 cents per foot in the plumbing section at my local 'big box' hardware store, Sutherlands.
• A yard stick - Home Depot sells an aluminum yardstick for under $2, but you can make a perfectly satisfactory gauge with a 3-foot piece of 1" wooden lathe for next-to-nothing. (For a 'professional'-looking gauge, I actually used a yellow aluminum 4-foot rule, but that was wretched excess at $5.)
• 3M/Scotch/Whatever - clear mailing/packaging tape. You should have some of this left over from the Christmas mailing season; otherwise around a $1 a small roll (and you won't need much).
• 2 short nylon zip-ties - You should have these in your garage. If not, buy them in bulk for cheap in the wiring section of Home Depot, Sutherlands, Ace Hardware, etc. - you'll use them and wonder why you didn't have them before.
• A tiny amount of automatic transmission fluid - Actually, just about any fluid works, including used motor oil, colored water, 2-stroke oil, etc. I chose ATF because I already had a gallon of it and (most important) it is really thin and is RED (which looks WAY cool as the indicator fluid against my fancy yellow ruler) and ATF won't hurt the engine if it accidentally gets sucked in the carb's vacuum port.
Building the Balancer
Fold your 20' of vinyl tubing in half and mark the center point. Lay your yardstick down flat on a convenient work surface (kitchen table or floor). Place the center point of the tubing at the bottom end of your yardstick (there is generally a hole at the top end of the yardstick - put the center-bend of your vinyl tubing at the opposite end of the yardstick from that hole). Carefully run the tubing up each side of the yardstick, making sure that the tubing makes a smooth, non-kinked bend at the bottom.
Use the clear packing/mailing tape to fasten the tubing in place on either side ( left and right ) of the yardstick. Thread the zip-ties through the hole at the top of the yardstick and snug the left and right side tubing to the respective sides of the 'stick with the zip-ties. You should now be able to hang your yardstick from the hole in the top ( I use a bungee suspended from a hook in the garage ceiling). The tubing runs around the perimeter of the yardstick and about seven feet of tubing hangs down from the left and right sides of the 'stick. I fold a piece of tape around each end of the tubing like a little flag and mark the left side with an "L" and the right side with an "R" using a magic marker.
Now, put one side of the tubing in the container of automatic transmission fluid and, using the other side of the tubing like a drinking straw, suck ATF fluid about three feet up into the tubing. Maintaining suction for a second, pull the tubing out of the ATF container and then raise BOTH ends of the tubing above the top of the yard stick. Temporarily fasten both ends of the tubing high enough that the ATF drains down to the loop at the bottom of the yardstick. I recommend leaving it overnight so that all the bubbles, etc. work their way out.
Once the ATF has settled into the bottom of the tubing, the balancer is almost ready to use. If everything has gone according to plan, you should now have a nicely graduated rule hanging from the ceiling with a thermometer-like tube running up both sides, with the red "thermometer" fluid about half-way up each side at identical heights. Cut a piece of black electrical tape just long enough to cover the width of your ruler and use it to mark the height of the fluid. Your super-accurate Carb Synchronizing Tool is now ready to use.
Synchronizing the Carburetors
BEFORE attempting to adjust the carburetors, you MUST have the other basic systems of the engine working properly: ignition properly adjusted (timing spot-on, advance mechanism operating properly), valves adjusted, compression within specifications, air filter clean, pollution lines leak-free, etc.
Warm up the bike with a ten-minute ride. Park the bike next to the Carb Synchronizer. Loosen the throttle cable adjuster lock nuts with a 10mm wrench and slack off the throttle cable adjusters until there is absolutely no tension on those cables - they should be loose. Disconnect the vacuum tubes that run from the carb nipples to the airbox (or remove the blanking screws or plugs from the vacuum ports, this varies between bikes - check your manual) and connect the right and left Carb Synchro Tool tubes to the respective nipples. Pick up a straight-blade screwdriver that fits the carburetors' throttle-stop screws and start the bike.
Synchronizing the Throttle Stop Screws at Idle
Unless you are incredibly lucky, the red fluid will begin to move, rising on one side of the ruler and dropping on the other. The fluid rises on that side of the bike where the throttle butterfly is more closed, which raises the intake vacuum. Gently turn that side's carb's throttle stop screw in (clock-wise) until the fluid movement stops, then just a touch more, until the fluid moves back toward equilibrium. As the fluid approaches the balance point (which you have marked with the black electrical tape), turn the throttle-stop screw counter-clockwise and STOP the fluid movement right at the balance point. Now check the tachometer for idle speed. If the idle speed is between 900 - 1100 RPM, you have the throttle stop screws perfectly balanced for idle speed. I like a 1050 RPM idle speed. If your idle speed is too high or too low, carefully adjust BOTH throttle-stop screws until the idle speed is within the 900 - 1100RPM range and the Carb Synchro fluid remains STOPPED at the balance point. Check to be sure you still have slack in both throttle cables. If so, the idle throttle stop screw synchronization is complete.
Important: the bike should NOT idle in the garage for more than 5 to10 minutes after being warmed up without a 'cool down' ride around the neighborhood or use of a BIG, high-speed fan, blowing cooling air over the engine.
Note: At this point, you may wish to adjust your Pilot Mixture Screws. Since this is not an absolutely necessary part of synchronizing the carburetors and is covered adequately in the various shop manuals, I will not address it here. If you do the Pilot Mixture adjustment, re-check the throttle stop screw balance and idle RPM and re-adjust as explained above.
Synchronizing the Throttle Cables
Now you must synchronize the throttle cables. Amazingly enough, neither the Haynes nor the Clymer manuals discuss this procedure, yet it is essential to smooth running, vibration-free highway-speed operation of your bike. Both throttle cables should still be slacked-off and their lock-nuts loose and the twist-grip will have a bit too much free-play as a result of loosening everything up for the idle adjustments. Carefully turn the throttle cable adjusters counterclockwise until MOST (but not ALL!) of the slack is removed from the cables, then spin the throttle-cable lock nuts down (clockwise) until they just BARELY seat. Re-check - there must STILL be some slack in BOTH cables. You should still be able to move the cable adjusters and lock nuts easily with your fingers. Start the bike. Idle speed should be the same as you have originally set it. Turn the handlebars to either side. Idle speed should not change. If idle speed or balance changes, you have TOO much tension on the cable(s) and must dial in some slack. If everything checks out, you are ready to synchronize the throttle cables.
With the engine running, slowly roll the throttle on until the engine speed picks up to 2500 RPM. Hold it there and check the Carb Synchro fluid. If the fluid is moving (as is likely), turn DOWN (clockwise) the throttle cable adjuster on the LOW side of the fluid until it stops, then moves back toward equilibrium, while holding the RPMs at 2500. As the fluid reaches the balance point, turn the throttle cable adjuster counter-clockwise and STOP the fluid movement as it reaches the black-tape-marked balance point. Snug the throttle-cable adjuster lock-nuts and re-check the balance by rolling on the throttle. If the fluid does not move from the balance point as the RPMs come up, shut off the bike and tighten the lock nuts. Re-check, including turning the handlebars to either side. If the fluid remains balanced, you now have perfectly synchronized carburetors. Disconnect the Carb Synchronizer Tool, reconnect the bikes's vacuum hoses (or replace the vacuum port screws/plugs) and go for a test ride.
I think you'll find, as I did, that well-balanced carbs make for a smoother Beemer.
Click here for a drawing of the balancer. It's a bit big, 89k, so download only if needed.
Hugh Kenny #6051
Cheyenne, Wyoming
Last Updated ( Sunday, 19 November 2006 )
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^^^ What In used on the V Strom and 4 Carb Trophies. Works perfectly. Takes mere minutes to make up, lasts as long as you want it to.
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One of the best things about the Morgan Carbtune is that you can lay it in a drawer, toolbox, etc. without it leaking out oil or toxic mercury.
The Morgan Carbtune is a very good tool. I have a super-expensive Vacuum Mate which is a useful diagnostic tool but for simple tuning a Carbmate is the way to go.
Twin Max is the sulkiest POS ever. It's better than nothing but it's still hateful. I gave mine away to someone wh's carbs were so buggered it didn't matter in the hope he'd get new carbs! :grin:
Pete
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I use a Carbmate also. Quick and easy.
http://www.amazon.com/CarbMate-TS-111-Carburetor-injection-synchronizer/dp/B0022XTDQA/ref=sr_1_1?ie=UTF8&qid=1450285676&sr=8-1&keywords=carbmate
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Made my own:
(http://i1177.photobucket.com/albums/x350/jtkirb/1005383_10201892798355885_1196199976_n_zps9d3f8adc.jpg) (http://s1177.photobucket.com/user/jtkirb/media/1005383_10201892798355885_1196199976_n_zps9d3f8adc.jpg.html)
clear tube, mounted to a stick, filled with fork oil
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I still have my mercury carb stix. Gauges, both mechanical and electronic, are calibrated against mercury and eventually go out of calibration. Keep it simple and stick with the standard.
Pete
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Am I the only one using vacuum gauges with dials and pointers?
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I still have my mercury carb stix. Gauges, both mechanical and electronic, are calibrated against mercury and eventually go out of calibration. Keep it simple and stick with the standard.
Pete
Carbtune does exactly the same thing, but without toxic mercury.
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I suggest before you use a Mercury manometer you google "Is Mercury Safe"
I certainly wouldn't use it where young children play.
I used to work in an instrument shop where we had a gold film mercury vapor analyzer. One drop spilt on the floor was enough to send the atmosphere in the room off scale. (above the safe working limit)
If you do spill Mercury get some Flour of Sulpher to dust around, that amalgamates with the Hg allowing it to be swept up.
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Am I the only one using vacuum gauges with dials and pointers?
My brother has a set of those. Watching those needles bounce around was painful.
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I suggest before you use a Mercury manometer you google "Is Mercury Safe"
I certainly wouldn't use it where young children play.
I used to work in an instrument shop where we had a gold film mercury vapor analyzer. One drop spilt on the floor was enough to send the atmosphere in the room off scale. (above the safe working limit)
If you do spill Mercury get some Flour of Sulpher to dust around, that amalgamates with the Hg allowing it to be swept up.
I was coating pennies with Mercury back around 1950. xrayed my feet in the shoe store a few times with a few hundred times the modern dose. Breathed lead and asbestos dust working in my Dad's garage doing brake jobs and leading panels before Bondo came along.
Had my Carb Stix since the '70s, no spills. I am fully aware of the toxicity. The carb stix live in my barn. Maybe that explains the lack of rodents.
Pete
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My brother has a set of those. Watching those needles bounce around was painful.
There are restrictor/damping screws for eliminating that on mine. They're very steady.
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I was coating pennies with Mercury back around 1950. xrayed my feet in the shoe store a few times with a few hundred times the modern dose. Breathed lead and asbestos dust working in my Dad's garage doing brake jobs and leading panels before Bondo came along.
Had my Carb Stix since the '70s, no spills. I am fully aware of the toxicity. The carb stix live in my barn. Maybe that explains the lack of rodents.
Pete
Hey, I played with the stuff too, and I have it in my teeth (the few left)
If I had a Mercury manometer I would probably use it too but not for balancing, oil's 15x more sensitive and has self damping built in.
I'm not suggesting you throw your Carb Stix out, just be aware that's all.
I don't believe liquid mercury is that dangerous but if your barn were to burn down turning all that into vapor it would contaminate a large area.
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Here's to add to Kiwi Roy and Ohio rider = make your own! (I made this based on someone's earlier post on WG - :thumb: :cool:)
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.
(http://i305.photobucket.com/albums/nn233/shawnsci/Guzzi/IMG_6605_zpsonxxilrm.jpg)
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"Am I the only one using vacuum gauges with dials and pointers?"
No. I use the four gauge set from Whitney. I added some aquarium air valves to dampen the flutter and manifold adapters from Parts Unlimited. Purchased the set in the early 90's so they may not be 50 bucks any more.
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Very pleased with the Harmonizer:
http://advrider.com/index.php?threads/harmonizer-vacuum-multi-tool-it-aint-your-daddys-twinmax.701625/
RPM read-out is handy for no-tach loops.
Also works well for slide balance adjustment (down at cruise RPM) - better than the drill bit method.
(https://i.ytimg.com/vi/ZRJOMPF49rw/hqdefault.jpg)
.
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Here's to add to Kiwi Roy and Ohio rider = make your own! (I made this based on someone's earlier post on WG - :thumb: :cool:)
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.
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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.
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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.
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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.
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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.
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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.
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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. :grin:
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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.
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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.
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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.
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+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.
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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
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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
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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.
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+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.
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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.
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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.
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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.
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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?
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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.
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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?
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The guys on the BMW Airhead site are extolling the virtues of the Grok Harmonizer. Anyone hear of it?
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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.
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I assume your idea is based on one of the inexpensive DP cells available, that will work.