DIY Carburetor Synchronize / Balance Tool
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- Опубліковано 28 вер 2024
- This is a homemade bottle style carburetor synchronization tool ( homemade manometer ) and balancing tool. If you are going to attempt to, or want to know how to sync your carburetors, there are a few things to know first.
1. Carburetor Synchronization = Adjusting your carburetor throttle plates or throttle slides so they move from your carburetors idle setting to wide open throttle simultaneously, or in sync with each other.
2. Balancing Carburetors = Adjusting your carburetors so they allow each cylinder to flow or pull the same amount of air and fuel at your desired idle speed. Carburetor sync and carburetor balancing go hand in hand.
3. Idle speed screw adjustments must be made at normal operation temperatures.
4. Air fuel mixture screw adjustments must be made at normal operating temperatures.
5. Air fuel mixture adjustments only affect your carburetors pilot circuit, which means from idle to part throttle. Air fuel mixture screw adjustments have zero effect on wide open throttle.
6. Carburetor running rich = Too much gas not enough air.
Carburetor running lean = Too much air not enough gas.
7. Wide open throttle rich or lean conditions are adjusted two ways:
A. Carburetors with throttle slides have a clip on the carburetor main jet needle. Raising the main jet needle clip drops the needle deeper into the main jet and will lean the carburetor out. Lowering the main jet needle clip will raise the needle and enrich your carburetors mix.
B. Carburetors with throttle plates (butterfly style) need to have the carburetors main jet changed to a larger diameter jet to richen the mix or a smaller diameter jet to lean your mix.
8. If your engine will not idle correctly or your air fuel mixture screws seem to have no affect on the engine at idle, then most likely your pilot jet circuit is clogged and you should clean it.
The snowmobile in the video is a 1986 Arctic cat cougar 500 fan cooled, it has Mikuni vm34 roundslide carburetors which have a primer nipple on the engine side of the throttle slide. Perfect place to attach a homemade manometer to balance everything. These mikuni vm34 roundslide carburetors were common on many motorcycles, snowmobiles and atv's. Suzuki, yamaha, polaris, arctic cat, all used them at one time or another, they are good carburetors when they are dialed in.
Hey Mike, Thanks for the info! I built mine using sauce jars and some $5 tube from Home Depot.
She runs better than ever!! I will try to remember to post a pic later!
THIS WORKS, PEOPLE!!!!!
Mike, I thought I had an idea on syncing carbs before I watch your video...I had no clue. The way you explained it is flawless and well enough that anyone could do it and you took the fear out that I had that I would mess something up. Thank you. I can't wait to try it and see how well both my bikes run afterwards.
After 56 years of motorcycling, I finally got a twin cylinder bike... Looks like I need two plastic bottles now. Thanks for the video..
That is the best damn tutorial I've seen yet! Great job! It is so simple yet so important. Again, great job!
thanks, I appreciate that and try to pass the info along the best I can
Jonathan Williams
mate that was really helpful … and nice to see a home-made method that blows away all those claims that you need to spend hundred bucks on a special tool! Thanks for taking the time to share that :)
Nice homemade manometer. FYI: If you bleed the air from that short transfer tube between the bottles, you'll be able to dial it in perfectly level across the bottles. Now I've got to add a third bottle to make it work for a triple!
I didn't know Robert De'Niro made instructional videos.
LOL
You talking to me???? I;m the only one here.... You talking to me????
Sounds nothing like him bro
Nice
Ha I was thinking this too!
That funny! Your so right! Lol
This is a great idea, if I could suggest using strong bottles ( Glass) as my plastic bottle rig just collapsed. I have a 1000cc motor which obviously creates lots of vacuum.
Excellent, followed what u were saying and it all made sense and I learned something. Before I always thought balancing the carbs on my old Honda was beyond me, some tricky magic I'd have to get someone else to sort, so thanks a lot to you and youtube, well worth watching.
Cool Video. I need to attempt this for my 3 cylinder XT snowmobile. The slides are totally wrong, so your video really helped me to figure that out. Thanks
Three and a half minutes in and I'm already giving it a like. Thanks for your time.
Could you also make a video on how you actually go about syncing the carb slides with the drill bits? That would be great!
Me too i got lost on that step,snooky.pa.
Great idea and I'm sure it will work perfectly when I get some stronger bottles. The ones I used were fairly thin plastic and instantly collapsed as soon as I started the engine... DOH!
😆. had a Homer moment "Doh!". lol
@@jake_break9185 not kidding. Moment of panic as I watched the water being sucked into the carbs 😨. My Mk2 version used plastic beakers with rubber sealed clip on tops. Works a charm 👍🏻.
While most of this is way different than my dual zenith carbs, I think that bottle sync tool will really help!
Thanks!
That's very CLEVER . Congratulations. From France.
Great easy to follow video ,love the milk crate vac bottle stand- nice and stable.
I built one with four inputs for my 650 Maxim and it worked great. THEN I left it in my Wisconsin garage over winter. Froze, broke, start over. Hint...empty the jars! Don't freeze!
very informative, clearly explained, i now know the diff between Balancing & Synchronization.
Excellent video man, I really appreciate it. On a side note though, that poor pool table xD
Eventually all pool tables in your basement become work benches; not sorry.
Well at least put a insert plate / board on the felt?
great video! thank you, but the idle screws only lift the slider, as soon as you rev the engine its all up to the throttle cable slack.. so your just really fine tuning the idle balance, but this method works well for fine tuning the throttle cables
Now time to sync and tune a triple and twin. This explained everything so simply thank you sir.
I built 4 carb setup 20 years ago simple balance vacuum hose on a flat board using motor oil as the gauge. Never sucked anything the gauge is 4 feet tall with another 6 feet of vacuum hose
I am going to start building one of these set ups to have on hand for my sled! great video 👍👍
This video is gold. So the point is to have fluid level equal at idle?
correct if thats what your after, I have many vehicles some with twin carbs, some with 4, my 4 carb bike wants to be synced at 3500 rpm due to engine vibration, but most vehicles, motorcycles, snowmobiles definitely want to be synced at idle.
Mike OD always check the service manual for your engine. My 1981 Honda CM400C says to perform the carb sync at 1200 (+/- 100) RPM. The guys who built your engine knew what they were doing!
MrNightpwner No, not the fluid level, the fluid level change rate null so neither bottle sucks from the other : level does not matter.
MrNightpwner @d
You can add 2 more bottles inline with the hoses to carbs which will ensure you cant suck water into the engine
Great little tool here. I have a manometer setup that I've used to sync carbs for quite a while and I use transmission fluid in it just in case it gets pulled into the carb so no harm would be done...but this idea is great. One thing though. You DO want the level of fluid in each bottle to be at the same height for the carbs to be perfectly sync'd. If one bottle has a level higher than the other then that carb is pulling more vacuum. It's not about stopping the levels from moving up or down, it's about the level of fluid being exactly the same in each bottle. If you have 1" of liquid in one bottle and 4" of liquid in the other when the levels finally stop rising/falling, then you are extremely out of balance.
That's actually incorrect, the level of fluid is irrelevant. All that matters is that both Carbs are pulling the same vacuum, if both are pulling the same vacuum then no fluid will travel between the bottles because the vacuum from each carb is cancelling the other out. So regardless of the level of fluid, if the fluid isn't transferring to another bottle then the vacuum is the same and your carbs and synced.
@@ledbetter1226 With all due respect, then I'm not sure you know how a manometer works. Different levels precisely means there are different pressures involved. That is exactly what a manometer does. Now, does a slightly different liquid level mean there is very much difference in pressure? No, but none the less, there is a pressure difference if the levels aren't the same. The one with the higher liquid level has less pressure, thus the liquid is "pulled" up to a higher potential plane...or rather pushed up by the higher pressure on the other side. I would say that "perfectly" tuned means equal levels. "Close enough" is levels not continuing to move.
Hi @@dilbone1 this system is not acting like a manometer, and so the principles are different. Manometers have a single liquid mass in a uniform U-shape tube with one end closed. They are initially calibrated for a specific purpose and then relative measurements are taken. External pressure verses the internal pressure of the sealed end of the system changes the height of the liquid in the tube. The system in this video has two separated liqid masses connected by a tube, where by the height of the liquid in one vessel has no impact on the height of the liquid in the other. A pressure difference will initiate a transfer of liquid, as both ends of the liquid transfer tube are at the same height, i.e. the bottom of the bottle. They only variator in this system is air pressure above the liquid surfaces in the bottles, as generated by the engines twin cylinders.
That being said, I think I agree with one of the above comments, that this will only balance the carbs for idle only. As soon as you twist the throttle the slack is taken up in the throttle cable, you are off idle and the idle screw position plays no further roll in regulating the balance of the system. So the best you can hope for is maybe better slow traffic. Close to and coming off idle improvements in smoother very low speed running.
@bobnewton6377 I'm not calling his set up a manometer. What I use is a manometer.
Syncing the carbs at idle means they have the same start point. Since they are linked mechanically I'm not sure why you're saying they would unsync off idle. However, one could certainly check balance at off idle RPM if so desired. I don't think I'd trust this set up for syncing carbs myself. I don't see it being sensitive enough
Hi. Thanks for your reply. If you read carefully I did not say they would unsinc, just that the noticeable improvement would only show at, or just coming off, idle. I hope that makes sense. 😊
Dude, you are a genius!
Very nice info. Thanks a lot. This will save me some money for sure.
Awesome explanation..gonna try this tonight..thanks
If the hose connecting the two bottles is filled with water, the two levels in the bottles should eventually equalize (without the device connected to an engine)
I agree with the principle here----He has gone to great pains to avoid sucking liquid into the carbs----but at the sacrifice of an awful lot of precision in setting the sync. This would not work well on syncing motorcycle carbs or injectors---which are synced to reduced engine vibration which 'puts your hands to sleep' Just using a plain old manometer would work better and produce a more accurate sync
Excellent video. I have one question do you think it would work if instead of using 1/4 inch fuel line to the carbs then converting them to fit the primer, if i just used primer lines all the way from the carbs to the bottles would it still work? I think it’d be easier than converting a 1/4 line to the primer
Thanks sir for your video. Really helpful!
I tried it, either it didn't work or my carbs were already synced. Can you get good enough vac from the oil injection fittings?
Great tutorial. Thank you
Very helpful, thank you for posting this video.
HI..i have 93 jaz Z...there no..primer plug, just the manual choke..where do I plug the hose to have the same result...tks
this is what I have my in mikuni triple. I have not done this yet however the primer kits are sold to take out the butterfly for the choke u can use those holes
has to be more accurate than gauges.
BTW, 320 grit sand paper will clean up those callouses on your wrench fingers
Great work bench you have.
WELL DONE! I have a corvair with dual rochesters. Ive seen the $45.00 tool that you set on top of the carbs after removing the air filters for balancing them. Would I need to make something to sit on top of these carbs?...no, because that would choke off the air right?...where do I hook up the tubes on my carbs?
How is this the most useful video to sync carbs in 2021
Mmm what do u mean I don’t need to look at the leaves? How else would I compare the tune?
Very nice tutorial! Is there a way that ican use this when my carbs dont have a vacuum?
My bike has 4 carbs. Can I just add 2 more bottles to the operation I assume? I dont feel like spending 1t0 dollars for a tool
I think that would work, if you connect them correctly.
Sounds like Robert DeNiro
what is that green hose attached to that jet on the left hand side of the carb for?
Primer
How do u do a 3 carb set up with the bottles
great videos thanks for the info.
Great video. Use glass bottles for motorcycles. Plastic will implode.
I like your explanation of how to adjust your carbs. I have an XLT triple. how would I build it (balancer) for a 3 cylinder?
I would hook up # 1 and # 2, balance them, then remove #1 and hook it to # 3, then balance # 3 to # 2 without adjusting number 2, only make adjustment to # 3 carb. Thats exactly how I balance my 4 motorcycle carbs, 3 is just as easy as 2
I was kind of thinking the same way.
Thank you.
On my 3 cylinder mercury. I was thinking to hook up 2 and 3 and synchronize 2 with 3. Then hooking up 1 and 2 and sychronizing 1 to 2. Since if you mess with three it affects both one and two.. would this be correct
When you are balancing them what RPM are you looking for on the TAC? Because you could balance them but be idling too high or too low, correct? So you want to balance them at the proper RPMs, right?
Hi Mike. Thanks for your excellent explanation. Would this method be usefull for a yamaha rd 400 ? it has 2 mikuni`s 29. I wonder if i can use the lubrication nipple (where the oil tank from premix is connected to the carb), because it doesnt have a primer nipple. thanks
No! DON'T do it. These bikes are ruined at this point. BUT! Good news, I will gladly purchase that old RD from you to that you don't waste any more of your time on it. Contact me to make arrangements to get rid of that Yamaha RD 400!
so lets say after carbs are synced iam fat at take off? turn both screws leaner or drop my pin
the air mixture screws only affect idle and 1/8 throttle, if you crank the throttle and your running rich, raise the clip on your needle, effectively dropping the needle into the main jet deeper.
Thanks. I will try that.
WHILST KEEPING AN EYE on the state of your plugs - as if they run hotter (leaner) you can burn though pistons....keep checking the colour and try to get it right on pilot jets first before going to the needles.......also bear in mind needles affect 1/2 throttle to full throttle
Really great video! :)
anyone else thinks this guy sounds a little like robert de niro?
i have been thinking that the whole time!
Sounds like every other New Yawker Ive ever heard or maybe BAAAsten.
you are brilliant man!
I have a 1989 ski doo with the mikuni vm34 carbs. The carbs have two vent tubes one on each side that hang down plus the nipple for the primer. As far as balancing with the bottle setup do I still hook them up to the primer nipple??
the vent tubes are overflow tubes in case your float needle sticks open and allows too much gas to enter the fuel bowl. On the mikuni vm34's I would absolutely use the primer nipple to balance the carbs. The primer nipple gives you straight engine vacuum.
This would only be accurate if you can be 100 per cent sure there are no air leaks anywhere in your set-up. a slight leak on one side or the other would bias your readings
awesome vid THX for making it
I have a 1400 motorcycle with two carbs I just rebuilt should this tutorial work for me?
Oidle screw ?
What about if you have more than two cylinders? Three cylinder engines seems tricky.
From other videos, you can have the bottom tubes connected, 1 to 2, 2 to 3, finally 3 to 1. Just add more bottles for extra cylinders.
Have a 650 articat v2 been sitting for threee years can you guide me to how to get it to run again strong
What if you had 3 carbs ?
You Rock Sir!
well done, good video!
Cool, thanks for sharing.
What about vet tube
did you hook them up to the oil injection. if so now your running it with no oil
primer port
I can't get past the fact that you treat your pool table with such disrespect. Have a JD and give yourself an uppercut.
Great video
Maybe I did something wrong on this, but I hooked one of these up on my MGB with Mikuni carbs and it collapsed the bottles down to nothing.
You need sturdier bottles that can handle the amount of vacuum. These poor man manometer solutions are typically and best done on small displacement motors where a carb feeds a single cylinder on this small motor. Vacuum levels are low in this setup so it's not hard to make a design that holds up.
They do make a sync tool just for the MGB and MG. It's not as cheap as a couple plastic bottles and clear tubing but it's far from expensive for a special tool at $29 USD (upon current google search). It costs 3x as much for a carb synchronizer for use on 4 cylinder motorcycles.
THANKS. MIKE SHOULD HAVE MENTIONED THE SUCKING PROBLEM ON LARGER ENGINES. i HAVE AN1100 V TWIN. MIKE THE SUCKBAG.
Yes but this don't tell me rich or lean . On the mixture screw . That's what in an having trouble with
Can you do this on a outboard motor
Thank you sir.
Carb sincro
does this work the same for a boat
Nice job, Thnx!
Thanks for the video. Does this work on mikuni sbn 46 mm,s ? It's off a jet ski. Dual carb.
While an awesome science fair project, why not just use a $10 vaccum gauge?
Great idea but why not buy a 29.00 tool that fits in a drawer in your tool box, doesn’t need water and ready at a moments notice.
The vacuum should be taken off after the slide or butter fly...
"You talking to me you must be talking me"
I recently tried this method but ran into trouble. Can anyone tell me why my bottles crush and try to pull fluid in ?
alex Martin this worked great for my snowblower, use 2 glass snapple bottles for motorcycles
how did you keep your bottles from sucking in ?
I HAVE THE SAME PROBLEM.
I switched to glass and the work fine.
Wow thanks for the tip
cool vid
Too bad one of his hoses blocks the view of the one bottles.😢
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
nice work bench . . . . \m/
Where do you hook this up on a Banshee?
watch the video - look for an external tube to vaccuum takeoff that goes to the fuel tap
Thanks that's great!
coll I have a set of wevers on a vw bug can yu help tank's
""Here we have 2 bottles of water, . ..actually they were orange juice bottles , but that doesn't matter now .. . ""
Entertainment from the start #
Great video
I saw the conment for 3 carbs.... How do I do this with my 4 carbs on my Ninja?
if you look down at the carbs from sitting on the bike and call them 1,2,3,4 from left to right, first balance carbs 2 and 3, then hook it to 1 and 2,balance carb 1 to carb 2 and only adjust the #1 carb to match it to # 2. Then hook it to carbs 3 and 4, and only adjust carb 4 to match carb 3. Done, its actually very east to do.
Perfect! Thank you very much for getting back - I set out 4 bottles at first and started thinking, now how in the hell am I going to route all 4 together lol
- then I was going to do it 1 to 2 then down the line - good to know to start on 2 and 3
I will let you know how it goes!! Thanks a ton!
Use glass anapple bottles not the plastic for the streetbike
Snapple
Damn - got plastic Gatorade lol
And what we do is....
The liquid specific gravity is not accurate...
Jk... Thank you for the decades of knowledge!
Thanks.... :-)usefull
CBD VAPE at the right bottom of the screen lol
my first thought was he must not play an awful lot of pool at home
After all this, the damn hose is in the way