Homemade 4 Cylinder Carburetor Synchronizer/Manometer

[@chyeong2518]

Really cool and practical idea. Cheap to make. It maybe more sensitive than the 4 individual vacuum gauges.as you are comparing all 4 cylinders relative to each other in one go. Get a great sense of achievement as a DIYer

[@guaporubio]

Ingenious device! I was in despair because of the difficulty in finding a gauge type synchronizer. They are expensive and only appear to be available through the internet. Hence shipping charges too. Thanks for posting this money saving brilliant solution.

[@CM-ec5jh]

I put mine together and I got water going straight through the number four carb. I have the line on number two vaccum line with a Tea to the bottle and vaccumm to the xj 750 tank. Craig

[@mattohley]

Awesome setup bro! I was about to drop @ $100 on some vacuum gauges and ran across this. Seems very accurate and inexpensive. Thanks a bunch for taking the time to post this!

[@clintonearlwalker]

Very good, I had a 1980 CB 900 Custom, the book talked about using a manometer to synch the carbs, it said to get one with "restrictors" so that mercury wouldn't be pulled out of if. Fortunately, I never had to synch the carbs, the bike ran pretty well for the 25 years I had it. I traded it on a Goldwing, the carbs are buried so far down in it, I haven't even seen them yet after about 3 years.

[@trondwell13]

nice one - was going to make my own on a different principle but now need to study yours. you did well to let the revs rise - last time I did this I managed a check at 4000 revs without overheating and balancing at the likely average revs was a very satisfactory result. If anyone tries this or another design - note that individual damping (x4) will adversely affect your results (i am guessing yours isnt)

[@kcorbings550]

RPM was about 1800 during the video portion of my synching. The manual for my bike (of course, check your manual for your own bike) wants you to do it at 1200 RPM, but as you make adjustments, the RPMs will often increase/decrease with very minor adjustments so it's difficult to stay exactly at the recommended engine speed. Just make sure you keep it as close to recommended as possible as the lowest RPMs is where the synchronization is most important.

[@kcorbings550]

1. Yes exactly, the level of the fluid doesn't matter; it's just the *movement* of the fluid that matters. No/very little movement = synced carbs 2. Connecting the bottles like you described should be just fine. It's all just a matter of making sure each bottle is linked to the rest somehow. You *don't* want simply 1 connected to 2, and 3 connected to 4 (like I've see on others) without something linking the 1/2 and 3/4 pairs you've created. Otherwise you are only syncing 1 with 2, etc.

[@kcorbings550]

You are going to have to check your bike manual for that info. There are usually vacuum ports on the intake boots between the carbs and the intake manifold. Usually you have to have a special adapter (or make some, like I did) to screw into the port to be able to connect a host to it.

[@kcorbings550]

I used a "T", just like you said, to connection them. Buy them at a hardware store or you could use the 'tees' from a drip irrigation kit or something like it. Even brass ones would work if you can find them to fit your tubing. If you can't source them locally, try eBay or Amazon.

[@kcorbings550]

I think I bought 20-25 feet total. You'll need about 4-5' for each carb line so you can position the manometer in a good spot, plus a few feet for the connections between the bottles and Ts.

[@aterack833]

this will be so helpful, thank you, i knew there must be a method that takes the cylinder differences into account not just the carbs them selves, and depending on your accuracy to read the level this would be the most accurate way you could measure things, larger diameter bottles would increase the accuracy would they not? i would think the more fluid it takes to affect the level the more accurate it would be but it would take longer to see the differences take affect, you could make two, one with small bottles for the base adjustment then much larger ones for the fine tuning, also any leak would affect things, but you could do a pressure or vacuum test to make sure you have no leaks, i applaud you in your efforts and your video, i assume this has an affect on fuel efficiency? do you have any other tips besides ride style to increase the bikes efficiency? i know weight is one but how much does that really affect it? and chain and bearings should be another, but what is the best to get?

[@haxto1]

or you could just splice a used jet into each line (each jet must have the same orifice size opening) thereby reducing the volume of the fluid needed to effect observable change reducing the amount of vacuum needed to effect change. It just makes the device much more sensitive than using the full tube diameter, thats like swinging a tree as a fly swatter. Any little tube or reducer you can insert into the lines (remember ALL of them must be equal in I.D.) will do the the job.

[@danielsabatinelli]

i use 2-stroke motor oil instead of water or gas, i like it because its viscus and non-volatile

[@trondwell13]

but viscous causes the fluid to climb the edges of the tube making it harder to read - it also slows the reaction of the fluids=inaccurate

[@kcorbings550]

The purpose for that hose is simply to make sure there is a full circular path for the fluid to flow (especially between 1 and 4) making for a more accurate reading. It's probably not really necessary however since the fluid is incompressible and whichever bottle is strongest is always going to pull fluid from the rest. Ideally, if you could get a single + shaped fitting and connect all 4 bottles to it that would work best and save on buying multiple fittings.

[@MeatsackMiracle]

#2 is your control carb that you should be basing your measurements from, at least on my 1978 cb750

[@lukeschaeffer2551]

Tough to see if those hoses go to the bottom of the bottle or if they are an inch above?

[@milkweed728]

thanks for the vid it took me a few min to figure out how to assemble it but i figured it out thanks and keep up the good work.

[@kcorbings550]

Yes, you *must* use something stiff like glass bottles for just that reason.

[@almoriescholtz2967]

thank you for sharing. tried your method, however I struggled my ass off.... got a zzr 1100 c model. system worked fine just could not set up the sync process, due to number 1 keeps on sucking the plastic bottle and squashing it and number 3 keeps on sucking dry. I then went back to the bench set up and bike sound good and perform good. however I would like to know what I am doing wrong. please help.....

[@trondwell13]

airleak? carbs are way out of balance - you have to adjust the highest bottles down as well as the lowest bottle up

[@NotamechanicMark]

Almorie Scholtz FYI, if you have a high performance vehicle you can eliminate many problems using glass bottles instead of plastic.

[@chilo31416]

Interesting video. I wonder if using taller skinnier bottles would make it more accurate.

[@sinsilius]

You can find them in car parts stores, various connectors are used for window washers.

[@RicFlair3333]

How did you keep the bottle stoppers from popping out of the bottle? I used Snapple bottles, and had a hell of a time keeping the stoppers in place. However, thanks for the idea. Mine worked great.

[@RogerBarraud]

It's sucking, not blowing.

[@paweloskoczek]

what is the purpose of the hose going out from bottle 1 form the left side when looking at the video and joining the house joinder number 4 from the right hand side,? Can I just use two T shape joiner and use them for bottle nr 2 and 3 and from those joiners I will connect them to bottle nr 1 and nr 4 ? Iam not sure If that makes sense :/ thanks for the video a lot it saves a lot of money :)

[@kcorbings550]

Yeah, you *have* to use glass bottles for exactly that reason. You could also use tall liquor bottles as well. They would better than the bottles I used because the extra height and capacity would give you more time to adjust things if a cylinder is way off and pulling fluid quickly.

[@highimpactcpa]

I just wanted to get a couple things clarified. First, does it matter that all of the bottles have the exact same amount of fluid at the end of the sync? It seems like as long as fluid is no longer moving one way or the other that vacuum is equal between all cylinders. Second, I am building one of these and Lowes was all out of T-connectors. Will the sync be affected if I still link all of the bottles together (ie. 1 connected to 2, 2 connected to 3, and 3 connected to 4)?

[@seanhenderson8693]

Has anybody tried this on the keihin fcr flatslides?? I know on the keihin carbs it's critical to get your idle circuit balanced correctly as the idle adds onto the total fuel flow of your mains at W/O/T But they also have the adjustable air bleed under the ram tubes ontop of the carb, if you adjust the air bleeds will it show the same in the manometer as adjusting the idle mix screws?

[@TikkaQrow]

You should use transmission fluid or 2 stroke oil instead of water. That way if any gets sucked into the engine it'll just burn off.

[@rooster63]

I made myself one like this based on your video to synch my 88 GSX-R 1100R carbs after a rebuild (adjusted valve clearances first) but the plastic Gatorade bottles I used collapsed due to the vacuum. Are your snapple bottles glass?

[@rran5415]

hi i have a question.before starting do i need to make sure that all the fluid levels are at the same level ? i know that when balancing the level doesn't matter but at the beginning do i need to use same amount of water in all 4 bottles ? thx

[@kcorbings550]

I depends on the bike, but they are pretty standard. I put a link to them in the video description. Or, do like I did and buy 4 socket head screws that fit and washers from the hardware store and short piece of brass tubing. Drill a small hole down the center of the screw, cut the tubing into about 1.5" pieces, and solder the tubing pieces to the tops of the screws. The tubing ended up being a perfect fit on the tops of the screws and the plastic tubing from the manometer fit right over it.

[@liviociaralli9261]

Quick question - I just bought 4 vacum gauges for 9 bucks a piece. There is no water involved with the units, Just the meter and the tube. The box says its a manometer and its gauged . Why wouldn't it work if you are just measuring/adjusting air pressure from each cylinder. As long as they all read basically the same, and the bike runs well, wouldn't that be considered that they are synced. Just askin and if yes, a lot simpler and no chance of liquid aspiration

[@nancybazan248]

Hi, what liquid did you put? I'm from Argentina, greetings

[@kingsemo649]

hi with me, the cylinder 3 is always empty, whether I turn on the screw, in or out, it remains empty. all others are in the same height only the 3 remains empty what should I do

[@climbamtn111]

Great idea! I'm curious, if you can increase and decrease vacuum, don't you want max vac for max hp? In this case you would want max values on all cylinders. I can see where a digital readout would much better in that case. OR (afterthought) Are you simply adjusting the balance of vac pressure?

[@Docv400]

Carb Balancing is done to get the Vacuum between Cylinders to the same level at idle. You're basically synchronising the Carb Butterflies (in CV carbs), or the Slides (in Slide Carbs), so they all open exactly the same amount, for any given throttle position. A Water manometer will be more accurate than Mercury Vacuum Gauges or Dial types. You're not altering the Vacuum produced, you're just comparing between cylinders.

[@trondwell13]

max vac is probably at full throttle.....this isnt about max vac this is about getting to all suck the same amounts at tickover and doesn't affect power or max flow etc at full throttle

[@trondwell13]

John Doc. - balance at idle only - anything more is speculative

[@BuffMyRadius]

At idle the throttle's butterflies (or slides on older carbs) are limiting how much air can get into the intake track so the vacuum will be high. When you pull the throttle the butterflies open, allowing more air into the intake track and the pressure comes up closer to atmospheric pressure. Because valves always open the same amount (in non-variable valve lift/timing engines) it is the job of the throttle body to essentially "hold back" the engine by restricting the available air. Worn engines can actually be synced at idle and then come out of sync as they are revved because one cylinder is flowing better then others, usually due to dirt on intake valves. This isn't really an issue though as you tune each carb to its own cylinder. Syncing is really only important at idle because each cylinder is operating at the very bottom of its performance potential where any error means that a cylinder might not be getting any air at all and it won't be able to fire at idle.

[@trondwell13]

Shed Man - Synced carbs probably move the same weight of fuel air mix.....the needles/pilots adjust the ratio of fuel to air. There is NO such thing as a PROPER sync gauge. I guess though you are referring to a damped diaphragm and spring gauge or a flow meter with damping - both of which leave the factory on Monday nominally reading some fictitious absolute air pressure measurement . By Tuesday, still in their packages they will no longer read the same nor again on the wednesday......too many variables eg phases of the moon, position of the tides, density of air, moisture content, internal friction, spring constants, damping rate, frequency response - to name but a few.......in other words NO WAY accurate. Ask yourself how an engine can suck blow bang on 720 degrees and the meters are set to give a steady reading....So why bother having 2 or 3 or 4 gauges when the only thing you hope to read is differential pressure Today. Tomorrow of course they will all be out of sync again as no carb will be linear and identical to its partner - the sun has only got to shine on the opposite side of the bike on the way home.....You make assumptions of what carb affect what in a group - so what when they are different (and all firing at different times)? You are only interested in getting them nominally the same on a day at tickover - the rest of the time it does not make one hoot of difference..... Your last line is a truism - as carbs usually share the same airbox

[@photography.naturally5760]

I'm curious how you make the adapters. I know you say specific to bike make/model, but how do you make yours? I have heard of using hex head cap screws and drilling thru them, but that seems like a lot of work?? I'm curious if there is more simplistic way?

[@kcorbings550]

+Photography.Naturally I used hex cap screws drilled through, with brass tubing pieces soldered to the head.

[@gellum]

I'm not sucking anything!

[@trondwell13]

you dont need to - just adjust the carbs till they level

[@AlienationIsReal]

Thats not what your boyfriend told me.

[@timothytime4176]

where do you get your pieces that actually screw into the bike, what are they, and how big?

[@kcorbings550]

Any good hardware store should have them. Even the big box stores like Home Depot or Lowes often carry them now.

[@eliaszepeda8561]

What did you use for fluid ?

[@flowmaster2010]

what is that black top you are using to push the tubes through? and where can i buy some?

[@hooseyad4ddy694]

what kind of liquid is used? does it not matter??

[@kcorbings550]

They are just rubber stoppers I got at the hardware store. Go to a *real* hardware store and they should be easy to find although I did find some at a Lowe's once but the hardware store actually ended up being cheaper.

[@runsolomon]

Damn it please tell me where to get the brass fittings

[@LB-el8ve]

Hello I'm from Brazil very well your project. I wonder what part that you use to connect the hose (T)

[@jorgecanale6660]

Digo, y si te comprás un manómetro no gastarás menos combustible, estuviste media hora acelerando para poder dejar los carburadores mas o menos como corresponde.

[@ComandanteJ]

+jorge jimmy Canale ...un manometro decente (uno que no empiece a saltar por toda la escala haciendo de su uso un calvario) cuesta bastante mas dinero que la gasolina extra que se gaste respecto a este metodo.

[@Klazudid1]

jorge jimmy CANALE

[@jackavery2554]

just get a Carbtune or Motion Pro, less headache easier to figure out

[@trondwell13]

"I would use gas" - Funny - I am only disappointed you said check it against a "bought" system - it is because of the inaccuracies, random damping of the shop systems that I go to a manometer particularly when the damping is a single common system shared. Thus you have no need to wonder if the damping is the same.

[@kcorbings550]

Close! It's a GS550.

[@concrete981]

I just built one and tried it on my 1100 vtwin. THE 2 PLASTIC BOTTLES SUCKED IN, OR SQUISHED. IF I USED GLASS BOTTLES WOULD THEY EXPLODE.

[@madclown2029x]

Nope. The reason glass is used is because it will maintain it's shape under the relatively minor pressure generated by the carbs. Plastic is too weak, which is why you can deform a plastic bottle with your lungs. So basically, use a glass bottle.

[@jeffmech600]

wouldn't 4 vacuum gauges work better?

[@RoaldvanDijkenHOT]

jeff i These do the same as any other manometer, perhaps even better since the deviation is minimal (assuming there are no air leaks). But this just cost around $10.- instead of $80.- for a set of gauges. Plus you have the satisfaction of being a DIY king. What I do miss in this video is at what rpm he does it and there's no warning for overheating air cooled engines while doing this.

[@kcorbings550]

+Roald van Dijken The RPM for syncing depends on the motorcycle model so always check your manual. This was between 1500 and 2100 RPM. Usually it will be slightly above idle. As a general warning, yes, always use a fan with air cooled engines when doing extended tuning sessions.

[@killer2600]

The 4 vacuum gauges would have to be calibrated to each other and have the same response curve but yes you could use 4 vacuum gauges if they were good quality and able to be calibrated. It's not really ideal because such gauges are expensive and sensitive. You have to really dampen the vacuum fluctuations otherwise the gauge needles will be wildly bouncing making them hard to accurately read and hard on the gauge itself.

[@BasicPoke]

Comercial dial vacuum gauges may not be accurate enough. You would not know the accuracy. For example one could be reading 5% high, another 5% low. With a fluid, it is perfectly accurate. The commercial ones with mercury would be nice, but expensive.

[@timothytime4176]

Where did you get the rubber stopper from?

[@6sigmajetkit]

If you use 2 cycle oil as your Synchronize fluid, getting some in the engine is not a problem. We include instructions for this in our Jet Kits. www.6sigmajetkit.com/

[@k7goober]

I need to do the same thing but I don't know where and how to connect the tubing to the bike any help?

[@kcorbings550]

There are so many reason *not* to use gas that I won't even try to list them all. Please don't even consider using gas for this project. The whole purpose of the design is so that you can't suck anything into the engine anyway. *DO NOT USE GAS*

[@maxims.762]

Why did you connect 1th bottle with the 4th bottle? thnx

[@maxims.762]

+Maxim S. mean is it enouhg to connect just 1&2 2&3 3&4 with tubes without the "reservoir"?

[@kcorbings550]

+Maxim S. Functionally, yes, it is the same, but it makes it easier to fill the tubes with fluid and keep air out.

[@maxims.762]

+kcorbings550 Thnx man!

[@tombair1401]

That's pretty cool but at 28 bucks on ebay I'm glad I didn't go to all the hassle to build that

[@kcorbings550]

I added a list in the video description above.

[@rooster63]

Thanks, will get 4 large bottles of liquor and empty them...on second thought, I'd better just find 4 empty ones! I can just re-use my hoses and t connectors

[@Tr1pMind]

i tried using plastic waterbottles today, they do NOT work, flex way too much lol glass bottles are a must

[@mikecb900]

hi ive copied what you have done but my plastic bottles are collapsing on start up should i be using glass bottles thanks mick

[@trondwell13]

the empty bottles AND TUBES self fill once the vac is balanced more

[@kcorbings550]

+Dan Barclay Great point: once a bottle goes dry, it is possible to just keep running and open up another carb more to pull enough fluid back into the dry one. Preferably not your original reference lowest vacuum cylinder.

[@trondwell13]

And I have never found such an accurate stable method where you can hear all the cylinders come in on song exactly according to the readings - unlike gauges that merely get close. Whilst not having to go to any great lengths checking the accuracy or setting up.

[@RogerBarraud]

Extra points if you can come up with a method to eliminate the set-screw backlash so it's not as frustrating as... :-)

[@BlizzardHockey4432]

Is this a cb? Or an xs?

[@kcorbings550]

GS 550 :)

[@lesleywoodward2990]

BlizzardHockey4432 h

[@ergner]

How can carbs air-fuel adjust?

[@killer2600]

That sounds more like a how do carbs work question and the internet can answer that query. Simple answer is the various needles and jets control the air/fuel mixture ratio.

[@zochpeter]

is that a GS1000??????

[@kyleyoung5470]

Peter Zoch that’s what I thought when I saw it!

[@edstastephenson9386]

I think it would work better if you tap off the bottom of the bottles so it automatically levels itself

[@Alien937]

Can't be as accurate as a set of Morgan gauges, I think I'll stick with something more accurate

[@rickjames3034]

probably more accurate than gauges to be honest, as long as all the hoses are the same length and bottles are the same size, how can there possibly be any deviation?

[@1jamesmimi]

nice 👏👍👌

[@jorgecanale6660]

La traducción de You tube a cualquier idioma, es un desastre universal!... no se entiende nada de nada!!!

[@Ihavetruth22]

His explanation isn't that great. still good vid. there are others out there.

[@buskman3286]

An amusing home experiment but for actual use - Jeez...just buy a gauge. You can do the check with a single gauge if you cannot afford a multi-gauge set.

[@michelgilormini2709]

L mec s'est fait vraiment chier pour sa réalisation type USINE à gazs.

[@luisar1977]

Porfavor en español..

[@destroylonely777]

Dad

[@lantasreskdr]

pertamax ;v

[@altlandf]

Just what's going on with this? Why does the engine suck the one of the bottles dry? Why do the carbs need to be synced? That makes no sense to me. I live in Pa and it's cold out. The bike is hard to start. It won't idle unless the choke is on. If I turn the choke off the bike stalls. The bike backfires also. When driving the bike it drives fine. It also has a swear word on YICS. Retarded smog crap they come up with.