Carb sync opinions

[bikerphil]

Speaking of cheap azz's has Phil made over to meet you yet Phil.

He's coming by tomorrow 'bout 11AM. We're gonna go tear up some Florida roads.

[rickmc2000]

Morgan "Carbtune pro"

OK, I'm sold. Where can I get my own Morgan "Carbtune pro"? A used one would be fine with me.

[natemoen]

OK, I'm sold. Where can I get my own Morgan "Carbtune pro"? A used one would be fine with me.

Good luck finding a used one! http://www.carbtune.com/

[fredintoon]

Awe yes, the nay-sayer as usual. If you love waisting money, go for the Morgan. However, you can achieve the same or better results with a home built, 4-way linked, vinyl tubing manometer for less than $10.

Hi 81,
as ATF is 13 times less dense than Mercury an ATF-filled manometer will be 13 times as accurate. Or at any rate, the fluid column height differences will be 13 times as big for the same pressure differential and thus, far easier to see.
However, to work right it'll also have to be at least 5 feet tall and will have to be kept upright.
Portable, it ain't.

[CatatonicBug]

Good luck finding a used one! http://www.carbtune.com/

Yeah, used Carbtunes are just about impossible to find, since everyone who has one would never want to get rid of it! The Colortunes are on ebay though, usually sold as NOS. That's how I got mine, and it cost just a hair less than getting it new from the UK.

[Ivan]

Awe yes, the nay-sayer as usual. If you love waisting money, go for the Morgan. However, you can achieve the same or better results with a home built, 4-way linked, vinyl tubing manometer for less than $10.

I have to totally agree with this. Cheap, and VERY accurate. The density of Automatic Transmission Fluid is much less than mercury or steel rods, so the fluid moves much further per amount of vacuum than heavier fluids. Also, there is the consideration that you are actually balancing each cylinder against it's sisters, rather than an atmospheric constant, or a spring in a gauge. So, that will increase the sensitivity and make the accuracy much higher. Believe me, its almost too sensitive. The pressure of the screw driver resting on a sync screw is enough to make the fluid climb 2-3 inches.

Also, my sync tubes are only about three feet long. Since they balance against each other, the length isn't required. The fluid just flows between each cylinder. The whole system may indeed be under total net vacuum. So, as you can see, the 5 foot sync gauge really isn't necessary.

And before anyone says it, there's only about a tablespoon or two of ATF, so your engine could suck it all in one cylinder, and while it would smoke like hell for a minute or two, it won't harm the engine a bit.

[dbeardslee]

There is such a thing as carrying accuracy too far with whatever type of gauges you decide to use. To be properly synced your carbs need to be within 2 cm of mercury of each other. On a carbtune, each line is equal to 2 cm vacuum, so when you've got them all dancing inside the same lines you're done. When you get to the point that you're barely cracking the screws, IMHO you've reached a point of diminishing returns. You could build a super accurate gauge, but unless you built some super accurate sync screws to go along with them, you're still going to wind up in about the same place.

[jwhughes3]

A little heat

Should get that fuel out of the Mercury. Mercury has a higher boiling point than gas.
Not that the carbtune isnt better, just hate to see you throw away the sticks. How DO you throw away Mercury? That much would involve the EPA I think.




John

I started with mercury sticks. It was great 'till a burp from the carbs sent fuel back into the mercury which effectively killed it. So I setup a 4-gauge synchronizer, and it worked great and was very accurate after calibration. It was however a little big to carry around, and I wound up buying a Carbtune Pro. Nice ergonomics, very accurate, and very compact. They also bundle it with a nylon case and a colortune plug. Unless you're good at setting your carb mixtures by ear or have an accurate tachometer to do it with, IMHO you need both tools (carbtune and colortune) to accurately adjust your carbs. My advice is to go with this - 14mm plug size.

[dbeardslee]

Actually, I kept the mercury in an open container for about 2 years and I think the gas evaporated out. Got some other contaminants on top of it from sitting though. I took a syringe with an 18 gauge horse needle attached, and drew the mercury out from the bottom leaving the contaminants behind. It looked pretty pristine when I packed it up and sent it to Catatonicbug (which is how you get rid of old mercury ). He used it to refill his neighbor's manometer, and I haven't heard anything from him since, so I guess it worked. Bug - anything to add?

On the sticks, when I was taking them apart one of the glass tubes broke, so if the gas didn't kill them I did .

[jmnjrpa]

+1 Ivan

Only difference is I use gear oil. It is very accurate and you have time to readjust before it is sucked into the engine. Tried ATF first and it sucked up before you could do anything. Also do not hook all four up first. Sync #3 and #4 then #1 and #2 separate before balancing the entire bank. When syncing, two plug the other two. It's been awhile since I did mine so if I have anything inverted will someone please jump in and correct me.


I have two Tees connected to a reducer Tee that has the reservoir.

[natemoen]

There is such a thing as carrying accuracy too far with whatever type of gauges you decide to use. To be properly synced your carbs need to be within 2 cm of mercury of each other. On a carbtune, each line is equal to 2 cm vacuum, so when you've got them all dancing inside the same lines you're done. When you get to the point that you're barely cracking the screws, IMHO you've reached a point of diminishing returns. You could build a super accurate gauge, but unless you built some super accurate sync screws to go along with them, you're still going to wind up in about the same place.

As you say this a thread from the UK board comes to mind..... http://www.benefiscal.co.uk/forum/in...p?topic=2903.0

[DGXSER]

You know, here I have been using this antique old mity-vac and going one carb at a time, adjusting back and forth and get done in about 15 minutes. I'm guessing about the time it takes to set up those tube manometers, and about 1/3 the price of the carbtune.

I'll defer to Mr. DBeardslee for the accuracy of my method. He put his 4 gage set on the same bike not to long after I had completed my work. I'm not certain, but if he turned a screw I'd swear it was only so he could turn it back and feel like it was worth the effort.

[dbeardslee]

Don - I had to adjust the sync a bit - but that was on a totally different bike, and you can't really expect different cylinders to draw the same. They were still pretty darn close, though .

[DGXSER]

Doug, I was referring to WAY back when a the time we were working on Mr. EGleaves machine, and we also colortuned and synched Thunderstruck. But yeah I do recall trying my method on one that you later hooked up, maybe Varnae's Goose.

[Ken Talbot]

There is such a thing as carrying accuracy too far with whatever type of gauges you decide to use. To be properly synced your carbs need to be within 2 cm of mercury of each other. .

Uh, I believe that should be 2mm of each other with a set of mercury sticks. 2cm would be a little over 3/4 of an inch, and that certainly would not be anything like close.