How to bench sync motorcycle carbs

[@nathanpowelldesign]

I'm really finding your videos to be an invaluable source of learning! As a new home mechanic I'm in a brave new world. You explain everything so clearly and in a manner that even newbies like myself can understand. You could make a fortune with all this knowledge your sharing Max, and I don't mean as a mechanic :) Many thanks!

[@mrmaxstorey]

Cool glad to help

[@jamisgood21]

That's great man! Glad to have you join the at home shade tree crew lol. I've learned and done my own things as much as possible for the last 10 years. Always learning. Best way to learn is to dive in head first sometimes!

[@philhart3724]

Nice first step. I use a short length of copper wire (cos it’s soft) adjust down on to it so that it JUST holds, then tip the carbs up and unwind the adjuster letting the wire drop out. Same with the other carb(s). Hi from the uk.

[@NeverSeriousPunk]

I took my carbs off again and cleaned them. Now it works beter than ever. Thanks for the vids. They help me out a lot. Keep up the good work

[@oldgit5948]

I had a real misfire and exhaust popping after a winter layup without draining the fuel. I needed to strip the carbs and clean the jets. As part of my diagnosis I tweaked the balance by ear and made things worse. So back to basics and try to set a datum balance was the next step. I found this video and did an interpretation using a small drill bit instead of the needle and a small piece of wood to lift the jets enough to measure. They were well out of synch and using this process worked amazingly well. After the rebuild the bike runs better than it has ever done in my 8 years of ownership. I have decided not to put in the garage for a professional balance because I don't expect much of an improvement. So thanks again for this video and I recommend it highly to anyone struggling with the same frustrations. Cheers, Tony

[@mrmaxstorey]

Glad to hear it Tony

[@lyndonmortimer4123]

I'm struggling with a 4 carb set up.i have walked away from it for a while.only I miss the bike so I'm going to have another look today. My problem is the rpm won't come.down.

[@xXxMOONSPELLxXx]

hey man i'm restoring a 1980 yamaha xs1100 and i don't know nothing about motorcycles (i don't even know how to ride one) and your videos have helped me really alot. many thanks from Juarez Mexico.

[@denebh733]

How did the restoration go?

[@ThrasherGnar]

Thanks so much for these videos, I happen to be working on my GS 450 L at the moment and now I have the confidence to tackle the carbs. Keep up the good work!!

[@jacobcarter811]

Hey bud anyway i can get ahold of you I am also working on gs450l and need info

[@BigFreeze0318]

Ive never even sat on a bike before. Bought a thundercat and it needed a carb cleaning. You saved me soo much mony and my cat runs way better. Thanks dude! subbed

[@keithnolan830]

Really nice straight forward bench sync video , we did alot of dynamic synching in college but this video explains things quite simply for those who have little or no mechanical knowledge , very well done sir , keep up the good work

[@MrChris4366]

Excellent video. I just needed to know how to get to the starting point after a rebuild and sync. Thank you.

[@allanbryers4682]

Hello Sir, Thank you for the video. With your instruction and taking my time, I was able to sync my 1993 Yamaha XV Virago750 carburettors. Many thanks. Al

[@chrisburgess19921]

brilliant video, searched all over to find what screws to mess with and i finally found it. thanks!

[@mrmaxstorey]

You'll probably be ok to just put them back on and back together so long as the adjustment linkage was not touched. The thing about bench syncing is it just puts it back to stock, which is fine, but what your bike really needs is for all the individual carbs to be adjusted to their individual cylinders, which have different needs as they wear independently. So go ahead and reassemble do a dynamic sync when you get a chance

[@Karl0459]

I was looking for an easy and simple basic set up method for my 4 carbs on a Suzuki GSX 1100 F and here I found it. Thank you very much mrmaxstorey. I will try your set up method this afternoon and I hope it will work. Best regards from germany

[@melliphile]

Thanks for helping to demystify motorcycle maintenance. Your videos are very helpful and I'm relieved to have found them. Keep up the good work!

[@MuzzleMike]

Thanks for making this video Max ! So many are afraid of malty carb set ups but I have learned that they are not as bad as I thought Working on my old KZ .

[@mrmaxstorey]

This method gets your carbs back to their baseline setting. its pretty close, but for optimal performance and smoothness, you should do a dynamic sync, using a manometer or the gauges

[@michaelmilton8925]

Back in my glory days of working on my Yamaha xj700 maxim I had all the good tools. Motion pro carb sync, yics stick 25$ tool yamaha makes you buy so you can sync em. cheap temporary plastic gas tank to run bike without original tank installed, up sized jets as far as I could go. Being a great motorcyclist begins in the garage. Trial an error method will get your machine back on the road. I even had this special tool that was a spark plug that you could look inside cylinder see what color your fuel/air mix was burning at. 75$ .

[@Viper6-MotoVlogger]

As usual, another great vid that is easy for everyone to follow. I think you do a great job of making people understand that they can fix their own bikes and not be intimidated!

[@walkerrog25]

I get called an "idle knob" quite often by mrs walker. Now I realise what it means :) enjoyed this so thanks.

[@MuzzleMike]

You are so right ! Mine could be a little better but they are so close I thought I would stop . Before it was a dog but now it burns the rear tire off and at times makes you think you need a change of pants !

[@Hot80s]

cleaned all jets & bench sync'ed floats & butterlflies my 1052 gsxr & it ran great

[@johnaustin5266]

Thanks max. Been looking for this post for a week now. My XV 535 balance is well out, can't start it at all. Now I can reset the carbs back to a 'factory setting' thanks to you. Now to trawl through you other vids. ;-)

[@granturismo93]

dude you are the freaking man bro. I knew I screwed up somewhere on my carbs gonna go back and sinc em thanks

[@Eagle3Tohoku]

Thanks for the awesome videos sir, You do a vary good job. I've done lots of work on my car but I'm starting work on my first bike and your videos have been a life saver.

[@adrenalinejunkeee45]

Thank you making this video! Help me tons in getting my 88 Hawk GT back on the rode!

[@liveandletlive2894]

Road!

[@mrmaxstorey]

Right on man, it really is surprising, in my opinion, how something as simple as a carburetor can do something so complex as making a bike go so fast

[@KaliKavala]

Superb video. Nicely explained and done as it should. GJ

[@MrBikercat]

thanks for the quick response.I'll pull the carb sometime soon and see what I come up with.

[@thestar111]

Great video, I will use this example to set my VFR400 NC30 back to default. Thanks :)

[@victorperezyproo6557]

Muchas gracias por todo lo que me enseñó, señor Max Storey. Gracias

[@CafeRacerGarage]

Amazing video brother:) thank you for sharing 👍

[@RONSUND]

Hi again and Greetings from India. I love your videos. I know of a better way to sync butterfly valves only on inline carbs with same side and positions. Pull out the idling screw so that the valves sit close completely. Hold the carbs against daylight and see through the intake side and press on the throttle to make sure both valves rise together.

[@johnhearne8773]

Good idea. I'm going to try this until I can afford vac gauges. I have triple Mikuni on my Triumph.

[@ShaunaAlexis]

This is an amazing video it is exactly what i was looking for because i have a 87 gs450l and you are using just that for your prop. love it keep it up.

[@gotredeemed]

Nicely done. Thanks a lot.

[@donovanlucibello379]

Simple. Brilliant. Thank you!

[@andrewl6751]

Dude i needed this video! Thanks so much!

[@hotoilhands]

Nice and clear. Thanks for this video.

[@kevinblaylock9883]

Inside the mouth of most motorcycle carbs is a pin head marker. The butterfly is adjusted until half way over the marker point for correct adjustments. 🙂👍

[@nofacemonster]

Thanks a lot man..... Really i think this is what i need to do for my Honda CD250U carburetors, I've been having a problem of right cylinder running rich no matter what i do, So this is what needs to be done, need to sync'em and i will let you know how it goes. Tomorrow i am gonna do it. Thanks a lot again :), My bike has the same engine as Honda Rebel 250, difference is it has two carburetors, I manage to get it running but black plug on right cylinder was never fixed :D, :)) so here goes.

[@mrmaxstorey]

OK well remember to first check the common causes of fouling plugs, such as fuel height, float leakage, improper jets, valves needing adjusting, or oil infiltration. Also, if you have the same motor as the rebel, remember too that switching to a single carb setup is an option for you if you wanted to install rebel parts

[@nofacemonster]

mrmaxstorey Thanks a lot man, IT worked, Yes i am thinking of single carb setup as well... if i can't get these right i will definitely fix a single carb which is easier, less tuning more riding. :), But it worked that synching thingy. Now i have another problem, left carb float valve doesn't shut off. So gonna work on that tomorrow. Thanks a million, Many blessings.

[@karimaatou581]

Hola

[@mrmaxstorey]

Yeah but sometimes the butterfly valves stick when you close them all the way. Besides, you would still have to use the idle knob to open them back up again a little so the bike can idle. If you can get it done your way then go for it, its the same basic principle

[@mrmaxstorey]

Not often, they are expensive and hard to come by down here. But Id really like to get the opportunity again

[@mrmaxstorey]

I like this method because I can use an actual tool which has uniform thickness, rather than just "eyeballing" it. It doesnt take any longer and it gets it just a little bit more accurate

[@mrmaxstorey]

Its the same process basically, just the carbs arent parallel so you need to change your point of view to make sure the butterfly valves are in line

[@genisisicon]

To be honest I just sprayed them and wiped them down. But I'm about to break it apart again. The exhaust is straight pipe and stock intake. I did change the plug and one plug was lean white.

[@genisisicon]

If I ever meet you I'm buying you a beer... Thanks bro

[@genisisicon]

Ok so it idles off of choke now... I actually had to back out the idle screw it worked so well. Took it for a quick stroll and same result under a load . 15 mph and she falls flat, stumbles and lean pops... I wonder if it's bad gas.. The bike has been sitting for a while..

[@brandonfulton1519]

Wish I knew about this method sooner

[@danielmarsolais1562]

Great video thanks. Trying it tomorrow.

[@w8lifter21]

Great info. Off to watch your other videos now :)

[@theonlyfunkydude]

Another great vid Max.many thanks

[@genisisicon]

Great video. I do have a question. On my 97 shadow " bobber" it start but won't idle off of the choke and at about 15 mph she falls on her face. I cleaned the carbs( didn't adjust)

[@weeverob]

i adjust my butterflies so both completely close off their venturies and then i adjust idle as necessary when the bike is idling.

[@rotriller1]

Rob Weaver hows that work for you? And inline 4s

[@isbemorph]

so you do the complete opposite what this video actually says, i also didn't know that idle screw is throwing off whole carb sync

[@BrentTheAussie]

Hi, this was very well done! I just did this on my Suzuki gsx 250f and actually ended up adjusting the butterflies with the needle in there. I actually though the mixture screws were the means for adjusting the carbies as I made a home made manometer which was kind of pointless considering that i adjusted the wrong thing. how do you adjust mixture screws on a 4cylinder 2 carby bike? The guide I used to make my manometer is found by typing in youtube: ''suzuki across manometer''

[@fireman9191]

Why not adjust the idle screw side second to match the other side, since it's way easier to adjust it?

[@JK-hd2zb]

No

[@mrmaxstorey]

Well the bike does need good gas to run. But I am very confident that you will also need to do a complete carb cleaning

[@chuckspeer2163]

Good info thanks

[@boogywoogynigah]

so i went with the pinesol method of cleaning my carbs. been soaking now for 3 days and looks great. now i gotta put everything back together and on! i had it synced a few months earlier but am wondering if i should perform this before getting them resynced or should i just get them resynced? i didnt take the carbs off linkages or mess with the adjustment screw so would i still have to get them resynced? im guessing yes. hoping not XD

[@mrmaxstorey]

When you cleaned the carbs, did the slides move up and down smoothly? Any modifications to the air intake or exhaust? Have you checked for vacuum leaks?

[@genisisicon]

I was thinking the same thing haha... Thanks bro.. Again good videos

[@BaMbOoZeD]

I totally forgot about the idle pin on my bike. I've just tried to sync my carbs on my fzr600r 1995 4jh and carb 3 is very low on my carbtool :/ so I saw this video again and thought ahhh need to use that idle pin also to sync carb 3 😋 the screw do not even touch the idle plate 😂

[@twopax17]

Is there no replacement to spending the money to get a sync system? They're usually only used once or twice for us non-mechanics.

[@chuckcunningham9653]

You said once you adjust the carbs/ butterflys that you should have what done? I didn't understand what you said. Thanks

[@mrmaxstorey]

+Chuck Cunningham Whats the time stamp?

[@dawidesterhuizen6989]

You should do a Dynamic Sync

[@onaduke]

Could you not adjust the idle carb to closed then adjust the synchronized carb to close eliminating the need to put anything in the chamber?

[@NeverSeriousPunk]

I just got done cleaning my carbs and put them back on and now my bike is very hard to start or wont start at all. When it is running when I use the throttle it back fires realy bad and doesnt want to run rigth. do you have any ideas what I can do to fix everything?

[@mrmaxstorey]

Not really, I use a small size. Now that the butterfly valves are synchronized, they can be opened and closed in unison via the idle screw

[@mrmaxstorey]

You can make one actually out of some long clear tubing, there are writeups how to do it here on youtube, but Ive never done it

[@kendavis8712]

Hey Max. I have a Honda 79 CB650 and I put pod's on the crabs with open exhaust and wanted your opinion on the jets I should instal in the stock carbs. I watched your videos on cleaning carbs and that was great. my carbs are clean, now I need to rejet. Your input would be appreciated. Thanks man.

[@mrmaxstorey]

Ken Davis Check out my carb jetting video for the process on how to figure that out

[@NackerWhacker]

Do you have a video on how to do a dynamic sync? If you don't could it be possible to do one in the near future?. Thanks,great detailed video as always ;)

[@mrmaxstorey]

Yeah its up there on my channel

[@NackerWhacker]

mrmaxstorey thanks it was a great help to me ;)

[@mrmaxstorey]

Adjust all of your carbs to the one controlled by the idle knob

[@aviinc6476]

For a rough bench sync you can use 4 ball bearings of the same size and drop them in the butterfly start to move the throttle until all the balls fall out at the same time. This is not a precision adjustment just a rough syncing gets you in the ball park

[@fieldmarshaljoe]

AVI inc great idea. I have little airsoft ball bearings and they’re a bit greasy from handling with fingers, would it still be safe to drop them in?

[@ImKumii]

Is the valve supposed to be open like that? It's closed on mine and it opens after "I pull the throttle". I've got issues with cold starts - I always have to wait until the engine gets warm to be able to ride, otherwise it dies or it shoots to exhaust (when its a bit warm). I've cleared the carbs, added a little bit of air-flow as I though there is too much gasoline... so its better but not what it should be. The bike goes like super-pumped at one point and then its just choked. Any help would be appreciated :)

[@yousifa3383]

Good job man .Thank you

[@mrmaxstorey]

You are awesome and everyone thinks so

[@brynew13]

i cleaned the carbs like this and for the three carbs i could get open they seemed clean but i cleaned them anyway, the bike runs for 40 seconds to a minute then i have to stop at a stop sign and it gives up i can start it once more before i have to walk it back to the house. could it be the one carb i couldnt get open?

[@Dannyboy1277]

Using an actual sync tool would obviously be the most accurate but can you sync by sound and how well the engine is running? I don't think it would work for more than 2 cylinders but for something like this you're really just trying to match the 2nd body to the 1st.

[@mrmaxstorey]

+Dannyboy1277 A sync tool is just like $40

[@vincentpilon3385]

Hi Max, I'm having problems to start a nonrunning GS400 1979. When doing the complete overhaul of the carbs, I removed the idle knob to get it clean. I forgot to take any references of the initial position of the butterfly. Can you tell me how I should adjust the knob as a starting point? Does this adjustment has a big impact on a nonrunning engine? And last question :) With the spark plug removed and the choke on, am I suppose to feel some fuel on my finger when I rotate the motor with the starter? Thanks for your videos and your help!

[@mrmaxstorey]

Dont worry about the idle knob too much, just screw it in until it impacts the linkage, and then about one full rotation after that. You can adjust it more later. And no you probably wont get much gas on your finger because you arent making very much compression with your finger there

[@vincentpilon3385]

mrmaxstorey Ok thanks! By the way, your videos about troubleshooting are awesomes.

[@mrmaxstorey]

Vincent Pilon Thanks Vincent

[@MrBikercat]

Hi, I have an inline 4, do I adjust the carb that's controlled by the idle knob first and then set my other carbs to that? or do I synch the two carbs on each side first and then synch the left to the right? thanks

[@philiprobertstone9771]

Well explained thanks

[@sin-nx1sv]

Have you got a video syncing a V-twin. Having trouble with my Suzuki vz800. Need to get it running smooth enough to get to the shop for a dynamic sync.

[@sinisakragulj104]

HELPFUL, THANKS!

[@philcarmichael6090]

Thanks for doing this, I was, have been told, LOL..will no doubtedly be informed many times in the future that bench syncing achieves absolutely nothing. All that crap aside, I worked on a set of 4 1982 Honda Goldwing carbs in order to get the bike to run correctly..a long process indeed. The setup on a flat four engine has many more tubes, hoses etc than your basic inline set, way too complicated for its own good... a basic Honda bloodline trait. I followed another persons tutorial on bench syncing and with very careful work on my part the carbs worked really well, so well that people who knew the bike prior said.."oh I see you went ahead and got a shop to sync the carbs with the proper gauges afterall" In short, bench syncing DOES have value.

[@mrmaxstorey]

Idle adjustment set too low?

[@MrBikercat]

Hi, just discovered your video. been having a problem synchronizing my carbs. I have an inline 4. the bike runs like crap. when I turn the adjustment screws. the needles on the vacum gauges don't move. I've turn the screws quite a bit and at some point I'll see blue smoke coming out of one of the exhaust pipes, but the gauge needles still doesn't move. would you happen to know the cause of this? also, if I follow your video will I at least be able to bring the carbs back to factory specs? thanks

[@geckhoe]

nice job, very informative

[@1996jonathanruiceco]

thanks man you really helped me a lot

[@daniellewinton2398]

How did you set the first carb? You turned something but didn’t show

[@mrmaxstorey]

twist the idle adjust knob

[@zacharyroach2870]

hey. hey max you would not happen to know why i have to hold my throttle slightly for my bike to idle would ya???

[@huimotorco]

Just curious if you have a video or advice on how to bench sync mechanical slide carbs?? Mine are Keihin PD50a style and the butterflies only seemed to be controlled by the choke, the slide itself is controlled by the throttle...any help appreciated!

[@mrmaxstorey]

***** Unfortunately I dont have a video up for that style carbs

[@brynbull6942]

Hi I'm trying to set up mine I can set the one side up.with the idle screw but when I try the other side and adjust the screw and nut the butterfly doesn't move any ideas would b a great help

[@mrmaxstorey]

Make sure that little adjusting nut is on the correct side of the linkage. Sometimes people will split the carbs when cleaning and then put it back together with the screw on the wrong side.

[@mrmaxstorey]

Thats what I like to hear

[@Logjam5]

Hi man. I have an old Honda and as well a couple of old BMW's; do you some times work on the German bikes? Regards, Alan Alberta, Canada

[@DOVIZ86]

Hey man, i have kawasaki gpz 500, can i use this sync method instead of that manometer one?

[@silentraven37]

i tried this on my mikuni's from my xj550 and something just wasnt right, every time i adjusted 1 of the carbs it would change the potion of the previous one. none of them ever seemed to be in a relative similar postion.... any suggestions?

[@motosports_46]

Whats the function of it? Why we do if not equal what bike do?

[@mrmaxstorey]

The function of this is to reset the carbs back to factory settings, if you needed to take apart the carbs for some reason. After you do this, you put the bike back together and do a dynamic sync, I have a video up for that as well

[@mrmaxstorey]

Cool glad to hear it

[@danbrewer9114]

Mrmaxstorey i'm stumped. I have a 2002 ninja zx7r that I just cleaned the carbs on watching your videos. Great informational videos btw. The cleaning job was fairly easy and it was my first time. Hardest part was getting the carbs off the bike. Anyways when I pulled the slide needles I noticed they all have #4 washer shims and the e clips are on the 3rd setting. All the main jets say 134 and the 2 outer mixture screws were set at 2 turns out and the two inners were 1 3/4. Stock setting is 1 3/4. When I bench sync the carbs with a needle and start my bike it hangs onto the rev like no tomorrow telling me its lean. So I tried backing in the screw without using the needle and eyeballing it and closed the butterflys a little more and it seems to rev out and not hang as bad. The exhaust sounds terrible though. Instead of that bub bub bub bub its bbbbbbbbb. I took her for a ride and it revved out nicely in first and then bogged in 2nd from 4k-8k making me think its to lean still. Any ideas or suggestions? Thank you for your time and great videos!

[@danbrewer9114]

I also forgot to mention that it has a high flow air filter and a slip on exhaust.

[@mrmaxstorey]

dan brewer Whoever added those mods didn't correctly jet the carbs. So you can either return the bike to stock settings by obtaining stock jets, intake and exhaust, or you can continue to adjust the carb settings by the method I show in my carb jetting video

[@altlandf]

I have 2 XJ650's. One is street legal and the other isn't. The XJ650 that's not street legal was to have had the carb professionally rebuilt. I couldn't get it running. I removed the number 1 spark plug and sprayed starter fluid in it. It fired right up but stalled right away. So I did it again and the same thing happened. So I removed the air cleaner and removed the spark plug and hit it with starter fluid. When the bike fired I kept spraying starter fluid in the air box it ran until I stopped it after 5 seconds. Sounded good but wouldn't take gas. Found out the so called professionally rebuilt carbs had this brown sticky crap in the fuel bowl area. The floats were frozen. Both engines are 5N8 and have the swear word YICS on the engine. What are the cylinder heads made of. Where the spark plugs are. The non registered bike has a spark plug that won't come out. It looks straight though. Today in York, Pa it was about 45 degrees out. I tried to start the bike that's street legal and all I got was a backfire. It didn't even try to start one bit. The petcock is working correctly. The battery is freshly charged. I am getting a fat blue spark. I changed the exhaust since I emailed you before. The previously owner of the legal bike had cherry bombs on the exhaust. I now have stock exhaust on the bike. It fits it like a glove. The gas was purchased less than 3 weeks ago. I am 45 and have NEVER had such a problem getting a bike to run right. I am getting float needles and seals soon. I am going to bench sync the carbs when they are off for the last time. This is the last gasp. I don't know what else to do. The bike wouldn't even fire with starter fluid. Compression is also good at 150, 145, 145, 145. I am at a loss.

[@Mirannaceste]

What was the solution?

[@victorperezyproo6557]

Las spreas que tienen 2.5 vueltas son las que estan sobre o encima de los papalotes que está usted sincronizando¿¿estas son de gasolina??

[@mrmaxstorey]

Depende a veces estan arriba a veces estan abajo de los carbs, estan tornilljos pequenos

[@namelesssnitchy]

How does your idle have to be?