I just synched my carbs on my 1980 Honda CX500. I'd never done it before and was nervous about it. Used your method and they synched up perfectly. Thanks for posting.
I too have a 1980 cx500. It's about to turn 20k miles. The original owner must have kept it in the garage because it is in top shape. The guy I bought it from was the second owner. He knew nothing about maintenance and had just had the valves adjusted and carbs rebuilt so I'm probably good to go for a while, but when it starts running rough, I'll know what to do. Great video.
awesome video, I have done a similar thing, but I used auto transmission fluid as it is an oil and if for any reason it got pulled into the bike it would be okay, oil good...water bad, I also found that the auto trans fluid was less jumpy in the container and showed more accuracy than water. used very successfully on a '96 XV1100S Virago. Paul.
Omg thanks!! I know it’s an older video but for any 2 carb setups this is pure gold. Was fiddling around with a hose filled partly with oil. Watching the levels rise to fast oil in engine aargh. This will make it much clearer!
THANK YOU SO VERY MUCH I was about to give up I bought myself one of these four gauge synchronisation meters, you could either choose wildly bouncing gauges or no movement at all as well as way too low readings. Out of desperation I used google and stumbled across your video. Recreated your tool and what should I say: IT’S LIKE HEAVEN works like a charm costs nearly nothing very hard to mess up ❤
I just sync'd my dual carbs on my 1988 Honda Shadow VT600 VLX using your procedure and manufacturing instructions for the homemade manometer. It worked great! One suggestion: Don't overthink the CW vs CCW thing about the adjusting screw. Just watch the tiny bubbles in the crossover tube (I used red ATF instead of water) and you can see the direction of flow. This is much quicker than waiting for the level to change in the bottles. Also, my screwdriver had to be in a vertical position, pointing downward from where the gas tank was attached ( had to remove the tank which turned out to be a good thing because I discovered a leaking petcock) which put weight on the adjusting screw, so I removed the screwdriver after each adjustment. I also "blipped" the throttle a few times throughout the adjustment. Total time of actual adjustment was less than 10 minutes. I don't know if it made a difference but I reinstalled the air filter housing after installing the brass adapter tubes and clear plastic fuel lines (5mm ID) for the adjustment.
Thanks a lot, just built my sync tool following your idea, and it worked great. Honda Transalp XL650V now purring like a big cat...too bad it's winter time here ;).
Great video and synch tool. Others may have said this, but the relative heights do not matter with the tool you created, only that they no longer move fluid between the two bottles.
A good monometer set up because of clear hoses to carbs NOT connected directly to carbs (just to top of bottles) so liquid doesn't get sucked into engine.Nice one ;)
Great Video! I need to sync my Yamaha Super T carbs, lost some power last year on a red line and I think this is the issue from what I've read in the forums. Defiantly a thumbs up on this one!
You mention at the beginning that you don't care for the gauge manometer because the needle keeps jumping around at idle. I wonder if you could simply use a damper in-line? Perhaps something as small as one of the bottles you are using for the fluid manometer or a bit larger? Ultra easy to try anyway. Just a two port rubber plug to stop the bottle and the air volume inside smooths erratic pressure/vacuum changes without altering the mean pressure/vacuum, kind of on the order of an anti-knock riser in plumbing.
I didn't mangle my hand via my bike but i did mangle my hand and my surgeon was talking about how hands are the hardest to put back together properly and in conversation we got onto the topic of Bikes and common injuries and hands are common as you put your hands out infront of you to save yourself.
That is cool. I gotta try this! Was thinking about using a light oil instead because if you watch @7:00 when you rev the engine, you'll actually see water vapor form in the bottles. Although a little water vapor in the engine is no big deal. And btw, did you know you can actually boil the water off with enough vacuum. Science 😉
Your balance job was dead on man. With this system you're not looking for the level to be the same, that part is irrelevant because all this setup does is show you a vacuum difference. You know the carbs are synched when the levels stop changing.
Vac gauges are plenty accurate enough, all you are lacking is a small air tap found on fish tank air pumps which needs to be closed down so that the vac gauge just stops pulsating. One for each gauge.
Thank you Forrest. Very good video. I like how you had an old motorbike also. Have you done this under a load, also? Say 2200- 2500 rpm, to adjust the cable lenghths? Ok, take care, Benjamin
OK Good Video, great piece of kit, but how did you adjust the screw between the carbs. I have the same carbs as the video but the screw and locknut are 'buried' between the carbs and I can hardly get near either of them to make an adjustment with engine running. It must be simpler?
I'd like to use the same method on a set of SU HD6 Carbs but I don't know where to connect the two synchronization tube's. Could it be to either the overflow or the suction pipe?? - Great video by the way 10/10
Nice video! I can't get one point: can I make this calibration even without cleaning the carburators first? I mean, I have my bike in here in her side stand, can I just try out your method or I need to do anything else first?
I’m going to try this. I tried the other method where they get a yard stick, 2 stroke oil, a 4 meter clear hose. That oil was jumping all over the place, fixed nothing.
Great DIY video guy! Who could not like this video!? Rev the motorcycle to around 4k rpm and sync' there or a reasonable cruising RPM. Syncing at idle isn't relevant as the engine spends most of it's time at cruising RPM's.
DUDE. I get carb- lexia every time I do this bloody job, so frustrating. I'm going to label each side CW and CCW straightaway before I do it again. That's brilliant.
In the beginning of the video he said he got the bottle idea from other people, as for the carburetor adjustments and what not, I would assume he got them from the FSM. (Factory Service Manual)
I tried a different set up and got water sucked into the carbs. Now the bike won't start! How do I get the bike to start again (it's a 2009 ninja 500r)? Going to use this method in my next attempt, thanks for the vid :)
Actual level in the bottles doesn't matter. If there is no movement (in the levels), then the Carbs (or Throttle Bodies on EFI Bikes) are perfectly balanced.
Thank you for making such a cool video , have fun on your bike and keep a watch out for idiots in vehicles that are not paying attention to bikers, be safe , smile and pat yourself on the back for a great simple easy to listen to and learn video . your a great guy ! Oh yes i will be making one of these synchro tools as soon as i polish off a couple brewskies lol... gulp gulp, and yes the fish in the fish tank are eyeballing me now hardcore, they know im about to rob the fish hoses lol, just kidding haha
while this synchronizer is a very good idea and quite impressive for it's simplicity i get a kick out seeing how much extra work people go through simply because they didn't know that all they had to do to calm the needle down is to restrict the volume of vacuum to the gauge with something like a fish aquarium needle air valve or even a little cheap inline plastic valve used in landscaping drip systems....
Thanks bro!!! You just saved me 70 bucks, and gave me a good reason to pickup a 12 pack.
Just in case you break 10 of the bottles trying to make it right ;]
Over six-years old and still totally relevant.
Cheers
You continue to amaze me with your clear understanding of mechanical devices and your ability to simplify them for those who don't. Good work!
I just synched my carbs on my 1980 Honda CX500. I'd never done it before and was nervous about it. Used your method and they synched up perfectly. Thanks for posting.
cool! i have a 1978 cx500 and was also kind of nervous about this but after seeing your comment i will try this this weekend
good to hear I'm not the only one that's nervous.
ill try this on the weekend.
Did the tubes fit right into the sync port or did you need an adapter? I have 1980cm400a so what worked for you I'm assuming will work for me lol
I too have a 1980 cx500. It's about to turn 20k miles. The original owner must have kept it in the garage because it is in top shape. The guy I bought it from was the second owner. He knew nothing about maintenance and had just had the valves adjusted and carbs rebuilt so I'm probably good to go for a while, but when it starts running rough, I'll know what to do. Great video.
You did a good job at explaining, btw the level difference in each bottle does not matter as long as if It does not move.
Exactly.
I did this and one bottle goes completely empty.
For someone who is new to motorcycles, and likes a visual representation of the effects actions have other than a needle on a gauge this is awesome!
Brilliant! CW and CCW.... rubber stops in the freezer. ...heard the sound difference. ..excellent video man.
awesome video,
I have done a similar thing, but I used auto transmission fluid as it is an oil and if for any reason it got pulled into the bike it would be okay, oil good...water bad, I also found that the auto trans fluid was less jumpy in the container and showed more accuracy than water. used very successfully on a '96 XV1100S Virago. Paul.
Great idea, seems more accurate than the commercial balancers. I don't drink so I will have to find some bottles from somewhere.
Omg thanks!! I know it’s an older video but for any 2 carb setups this is pure gold. Was fiddling around with a hose filled partly with oil. Watching the levels rise to fast oil in engine aargh. This will make it much clearer!
THANK YOU SO VERY MUCH
I was about to give up
I bought myself one of these four gauge synchronisation meters, you could either choose wildly bouncing gauges or no movement at all as well as way too low readings.
Out of desperation I used google and stumbled across your video.
Recreated your tool and what should I say: IT’S LIKE HEAVEN
works like a charm costs nearly nothing
very hard to mess up
❤
Glad I found your video. The vacuum tester Kawasaki recommends is $1,322.00 and I only paid $1000.00 for my bike, so. . . .
I just sync'd my dual carbs on my 1988 Honda Shadow VT600 VLX using your procedure and manufacturing instructions for the homemade manometer. It worked great!
One suggestion: Don't overthink the CW vs CCW thing about the adjusting screw. Just watch the tiny bubbles in the crossover tube (I used red ATF instead of water) and you can see the direction of flow. This is much quicker than waiting for the level to change in the bottles.
Also, my screwdriver had to be in a vertical position, pointing downward from where the gas tank was attached ( had to remove the tank which turned out to be a good thing because I discovered a leaking petcock) which put weight on the adjusting screw, so I removed the screwdriver after each adjustment. I also "blipped" the throttle a few times throughout the adjustment. Total time of actual adjustment was less than 10 minutes.
I don't know if it made a difference but I reinstalled the air filter housing after installing the brass adapter tubes and clear plastic fuel lines (5mm ID) for the adjustment.
Thanks a lot, just built my sync tool following your idea, and it worked great. Honda Transalp XL650V now purring like a big cat...too bad it's winter time here ;).
Your a genius man. I wish you nothing but luck and prosperity in the future .
That's probably one of the better setups I've seen on YT. Nice one.
Great video and synch tool. Others may have said this, but the relative heights do not matter with the tool you created, only that they no longer move fluid between the two bottles.
A good monometer set up because of clear hoses to carbs NOT connected directly to carbs (just to top of bottles) so liquid doesn't get sucked into engine.Nice one ;)
Made it two days ago on my Silverwing 2001. ! Huge deference! Thanks buddy!
Thank you for the clear and thorough demonstration. Great video.
that is freaking ingenuous!!! You are why this platform exists. Sharing useful simple daily tips. Good job!!!🖖👌🍫
Best sync vid on UA-cam and I have watch a lot of them.
Just did my own tool for my V star 650 and it worked great, thanks for the video.
Thumbs up for the carb sync animation at the end. Thanks for the video.
“Fish tank tubing” ichiban moto would be proud
Great Video! I need to sync my Yamaha Super T carbs, lost some power last year on a red line and I think this is the issue from what I've read in the forums. Defiantly a thumbs up on this one!
Paul spisak
Hey Paul,
Is that on the old 750 Super T or the new 1200?
You mention at the beginning that you don't care for the gauge manometer because the needle keeps jumping around at idle. I wonder if you could simply use a damper in-line? Perhaps something as small as one of the bottles you are using for the fluid manometer or a bit larger? Ultra easy to try anyway. Just a two port rubber plug to stop the bottle and the air volume inside smooths erratic pressure/vacuum changes without altering the mean pressure/vacuum, kind of on the order of an anti-knock riser in plumbing.
Thank you alot for this video, it helped me create this tool from scratch and i've synced carbs on multiple bikes with this!
I love the way you broke it down.
Your videos are the antithesis to the stupidity of youtube comments. Brilliant!
I like the freezer tactic. I have got four carbs to do on my Kawasaki 550 zephyr but I'm sure I can figure out the build.
I didn't mangle my hand via my bike but i did mangle my hand and my surgeon was talking about how hands are the hardest to put back together properly and in conversation we got onto the topic of Bikes and common injuries and hands are common as you put your hands out infront of you to save yourself.
looking for a way to synch my carbs on the same bike you have! haha! so this was fantastically informative. Thanks!
That is cool. I gotta try this!
Was thinking about using a light oil instead because if you watch @7:00 when you rev the engine, you'll actually see water vapor form in the bottles. Although a little water vapor in the engine is no big deal.
And btw, did you know you can actually boil the water off with enough vacuum. Science 😉
Lmao @ actually throwing em in the freezer take a thumbs up just for that.
This is an excellent vid, and very ingenious, cost effective, thank you 👍
moving the H at the end was cool lol XD
Your balance job was dead on man. With this system you're not looking for the level to be the same, that part is irrelevant because all this setup does is show you a vacuum difference. You know the carbs are synched when the levels stop changing.
and all you had to do is change one carb
best one I've seen yet!
Sound distinction was huge!!!
Amazingly!
Greetings from Belarus
HighFive!!!
Gonna try this out on my 82 Suzuki gs400 this weekend. Thanks.
Vac gauges are plenty accurate enough, all you are lacking is a small air tap found on fish tank air pumps which needs to be closed down so that the vac gauge just stops pulsating. One for each gauge.
Thank you Forrest. Very good video. I like how you had an old motorbike also. Have you done this under a load, also? Say 2200- 2500 rpm, to adjust the cable lenghths? Ok, take care, Benjamin
Great job, doing this on the weekend 👍
Great video and well edited. This seems to work and I will definitely be referring it to some friends
What a superb result.
OK Good Video, great piece of kit, but how did you adjust the screw between the carbs. I have the same carbs as the video but the screw and locknut are 'buried' between the carbs and I can hardly get near either of them to make an adjustment with engine running. It must be simpler?
I'd like to use the same method on a set of SU HD6 Carbs but I don't know where to connect the two synchronization tube's. Could it be to either the overflow or the suction pipe?? - Great video by the way 10/10
didn't even know such a thing existed thanks
Man, simplicity of your idea is awesome! Thanks for sharing this. Out of curiosity, is it possible to make this for 2+ carbs?
Just have to start at one end and do 2 at a time
It seems one could do a fair job merely by sound. Thoughts?
Nice video!
I can't get one point: can I make this calibration even without cleaning the carburators first? I mean, I have my bike in here in her side stand, can I just try out your method or I need to do anything else first?
Well done video. Thanks. I'm going to give it a try!
Great video, I will be making me one of these bottle indicators!
I’m going to try this. I tried the other method where they get a yard stick, 2 stroke oil, a 4 meter clear hose. That oil was jumping all over the place, fixed nothing.
My biggest question is how the hell did you get the lime slices out of the bottles? lol
This was fun!
I´m propably make one to!
Thanks!
Great video man
Thank you sir!!!! Cheap and appears to work.
Great DIY video guy! Who could not like this video!? Rev the motorcycle to around 4k rpm and sync' there or a reasonable
cruising RPM. Syncing at idle isn't relevant as the engine spends most
of it's time at cruising RPM's.
DUDE. I get carb- lexia every time I do this bloody job, so frustrating. I'm going to label each side CW and CCW straightaway before I do it again. That's brilliant.
dont forget to label which carb each is for, or you may end up backwards. (i.e. CW - Right Carb)
Again with the brilliance. Do you do taxes?
Awesome tutorial
I’m going to try this on my 89 gs500 ! Hope it works
Brother, if you set the air screw of the throttle, then the rpm will also change??

That's cool . well done .thanks for sharing.
The boat man, let's see the boat!!
In the beginning of the video he said he got the bottle idea from other people, as for the carburetor adjustments and what not, I would assume he got them from the FSM. (Factory Service Manual)
Good info, well presented. Have a thumb
I tried a different set up and got water sucked into the carbs. Now the bike won't start! How do I get the bike to start again (it's a 2009 ninja 500r)? Going to use this method in my next attempt, thanks for the vid :)
stupid question I guess but where did you get the rubber stoppers? Hobby Lobby or something?
nice video ! what did you take to conect the tubes to the cylinder ?
Im convinced you’re tom green
brilliant
Can you do this for 4 carbs? Same but to more? Or do you sync 2 carbs and then two?
Great video man! Hope this works for my bike.
Actual level in the bottles doesn't matter.
If there is no movement (in the levels), then the Carbs (or Throttle Bodies on EFI Bikes) are perfectly balanced.
to stop youre vacume gauges from bouncing use checkvalve in line a
bike sound real nice man. enjoy in and very funny out tro
Thank you for making such a cool video , have fun on your bike and keep a watch out for idiots in vehicles that are not paying attention to bikers, be safe , smile and pat yourself on the back for a great simple easy to listen to and learn video . your a great guy ! Oh yes i will be making one of these synchro tools as soon as i polish off a couple brewskies lol... gulp gulp, and yes the fish in the fish tank are eyeballing me now hardcore, they know im about to rob the fish hoses lol, just kidding haha
🤣🤣👍🔥
Great video! Really useful! Thanks!
can you bypass the bottles and just hook the tubes directly in the carb vacum ports ?
Nice. Where do you get rubber plugs though?
Just use a needle valve or a restrictor with the vacuum gauge and that will stop the needle flicking around
while this synchronizer is a very good idea and quite impressive for it's simplicity i get a kick out seeing how much extra work people go through simply because they didn't know that all they had to do to calm the needle down is to restrict the volume of vacuum to the gauge with something like a fish aquarium needle air valve or even a little cheap inline plastic valve used in landscaping drip systems....
Thankx man. Very informative
I have a 72 cb 750 4 into one long tube header kerker pipe love my bike
Thought the "h" at the end was a nice touch. Are you pursuing a major in college right now? And if so, what major?
Thanks for cheap and good idea!!! ;)
just double this for a 4 cylinder 4carb bike, simple and effective
Those screws under the carbs are not air but fuel screws
Thank for knowledge ❤❤❤
Great video! Thanks
Where do I get the fittings for the vacuum ports
ok sir
How would you make this for a 4 cylinder bike ??
Please learn the difference between pressure and vacuum.
Good job!
I have these carbs for my '78 CB400T II Hawk :)
Nice a buddy of mine is balancing for cards right now
What do you use to connect it to a 84 Honda shadow 700 I mean to the engine