1979 Honda CB750 Carburetor Synchronization

In this video we look at the carb sync on this 1979 CB750.
We learn the importance of double checking our work even after a perfect carb clean and bench synchronization and a fairly steady idle.
We see that fine tuning with this type of procedure is still needed with the proper tools to help make this bike smooth out at idle.
TOOLS USED IN VIDEO:
Carb Sync Set from K&L : amzn.to/3gRRdhF
Carb Sync Set (cheaper comparable option) : amzn.to/3GW4aRZ
Carb Sync Adjustment Tool (similar) : www.dimecitycy...
DOHC CB750 & CB900 Carb Cleaning Workshop
www.themotorcy...
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[@atombombsgarage]

Man, I really appreciate all the tips and tricks. I have been watching every single one of your videos preparing myself to rebuild and then finally tune my carburetors on my 81 cb900c. You’ve really made me understand the difference between fuel/air mixture screws, what your vacuum is actually doing, and your idle rpm speed. And just ultimately understanding what the carb is doing. Thanks for the videos.

[@mcporter03]

I have a 79 cbf750ss that needs ❤️ and a new home! This will be just what I need !

[@LadyKSailing]

Your videos are PERFECT my dude. Length, quality, and the technical level I think a lot of us needed to see! THANK YOU THANK YOU THANK YOU!

[@curtsalomon5687]

finally a good sync vedio on these carbs

[@ClassicRider]

This is the same as my bike, which I bought brand new in 1979. Today, my wife and I traveled 130 miles on her. Lots to talk about, learn and share. I restored my beauty during shelter in place, since 1988 when having to store her away to raise my family. I have morre work coming up, but will share it later. right now, I want to see your video on the Limited Anniversary Edition 1979 Honda 750.

[@ClassicRider]

Thats not the Original Exhaust - it certainly sounds like mine during cold start up - btw: I just priced your carb syncer - question, do you travel to New England?

[@lynnh7694]

Dude, your in the zone right now. I just got my tank and side covers back from the paint shop, hopefully my project bike fires up this weekend.

[@chuniquepaceno470]

Thank you so much, this video will be very useful as I've been meaning to do this adjustment for a while.

[@josephcottone9613]

My old gpz had a chop like that at idle. I Love it! I’m going to “tune” it back into my next 80s bike. Haha

[@fitzstermoto]

Another great video! I ended up buying the same exact carb sync tool set last year and it's been fantastic! Thanks for all the tips and tricks and I'm loving the newer videos! Thanks for sharing Cody!

[@TheMotorcycleMD]

Glad to hear brother! Great tool indeed!

[@cylekeltner1261]

So glad I found your channel....

[@marcusscott9800]

Outstanding video Cody! Great tips and info! Keep up the great work!

[@AICD1999]

Welcome back! Hope your feeling better.

[@TheMotorcycleMD]

I am! Lots of work to do, thanks for sticking around!

[@anthonyludo7416]

Thanks Cody for this very useful video. You do a priceless job helping us like that. 👌

[@vermhot]

This was a excellent video ! Cleared up a lot of questions I had !

[@cri8tor]

Great tutorial. Would like to see more of these types of videos along with more content on the 2003 Honda Shadow, but that's because I own one. Cheers MD

[@hellomynameismachine]

Loving these very informative videos. Thank you!

[@jerrys2346]

Super helpful as always. I might need to get your rebuild class for my newly found 1983 CB1000 Custom. I bought it at an estate auction but still have to get it running. Wish me luck!

[@TheMotorcycleMD]

Right on!

[@kaseyk2701]

I also just scooped up a cb1000 custom. as well, figured there kinda a oddity. Always see the 900s. awesome man! Hope it works good for ya!

[@jerrys2346]

@@kaseyk2701 I did get end up getting Cody's CB900 carburetor rebuild online tutorial...and now my CB1000 is running. I highly recommend it.

[@sthildas4857]

Great work Cody, easy plus simple to follow, thx for your help. 🏍️

[@augustharlacher5660]

Hey Cody: Thanks for the awesome video! I learned something today! Thanks again Brother!😎👍

[@andyMSH700]

Super cool dude....great video and i am going to follow your instructions so thanks. Good idea is to spray wd40 on bike frames if u r not going to restore and paint them....keeps them perfect.

[@marksaunderson3042]

Nice bike. Hope you managed to get it back to showroom, and looking like it was weeks old, not years old. And I can hear the clear difference. Running shirt v’s running nice.

[@TheShrewdServant]

Thank you for your time!

[@magnum357225]

Great job, i have the same tool works wonders, just a sugestion u want to get ur bike to 1500rpm and then do adjustments, on 4 carbs center two first and then sides

[@massoudzadeh3394]

Cody, I wish you were in California. I love your videos. I have learned so much from your videos, but I kind of scared to mess with the carburetors.

[@daveco1270]

Always glad to see Cody pop up in my KZbin feed. Great video. You made it look so easy. On my 75 CB750 it seems like I'll get carbs 1 and 2 synced then when I adjust carb 3 or 4 the others go out of sync...and it's like that whole time...I adjust one and it effects all of them. Eventually I'm able to get them close enough. What RPM's do you have the idle at when you start your sync? Why no JIS impact to get those screws out?

[@chillywilly3397]

Great video. Thank you for the tutorial. You got a new subscriber.

[@colinculverwell325]

Interesting reminder of how much space there is on those 70/80s bikes. Just done the carb sync on my FZ1. The adjustment screws are tiny, buried deep down with coils, cables and pipes over the carbs.

[@TheMotorcycleMD]

Ugh, that sounds horrible but I know what your talking about!

[@wherethereisfaith]

Hey Cody, I have a 1995 Honda Magna VFR750. I was having part throttle miss so since I bought it not too long ago, I decided to put in a new set of NGK plugs. It fixed the problem for a little while then it started this misfiring thing between 2k and 3k engine rpm again. The plugs I took out were all black in color except for the cylinder right next to the ignition switch. The threads were also wet with either gas or oil, think it was gas cause it was pretty thin. My local Honda shop won't touch it cause its too old

[@senate2042]

I want a 750 to add to my stable.. definitely ordering one of those adjustment tool... it's a pain using a screwdriver and a wrench

[@TheMotorcycleMD]

No kidding! That tool is a game changer.

[@elderrider9298]

great video

[@vmaxmuscle5612]

Thanks Cody

[@davidgridley3643]

Nice work

[@TheMotorcycleMD]

Thank you! Cheers!

[@rustyjames4962]

Great stuff spot on I have an 82 same bike 3,846 miles sat a long time till I got it a few days ago runs on choke wont idle right I cleaned out carbs they were not shabby I noticed it runs hot like it's to lean I've got air set at 2 and a half out now it runs worse what did I do wrong?

[@connergunnoe5576]

Love the video! Question! Will this video be a decent reference on how to do my 1979 CB650?

[@karlwalker1771]

King OF DIY SIR! And rightly so Mate. Any chance of a VTR 1000 FIRESTORM/SUPER HAWK V twin Carb Setup Cody :) Love the channel

[@ClassicRider]

Hi MD - I really got a problem and need your guidance. btw: I have that Limited Edition and ride it all most daily . Got it in 79. HELP - About a month ago, I got a 1981 CB750 Custom that has stacks and no airbox - Engine worked fine. I got it for my wife, and have done a number of repairs. Mater Cylinder, Turn Signal Switch, electrical shorts, etc. Similar to how the 750s' loose power when needing to go to reserve, suddenly "Babe' would loose power then jerk forward in full power. I assumed it was a dirty tank. Babe has a dirty tank, but does not seem to be the cause. The fuel regulator diagram that is mounted on top of carb 4 - the over flow tube would drip. I plugged it, and also found a replacement. Problem went away until I refilled the tank. So I added some gum out like before hoping that and spraying carb cleaner into the fuel hose going to the regulator diaphragm from the tank could correct issue like last time. Suddenly no fuel is getting to the carbs, but plenty going to the regulator diaphragm which has a vacuum hose coming from carb 2. I tried draining No 4's fuel bowl which appeared empty. Consider that Babe behave is running out of fuel, than that this regulator diaphragm might have an issue in letting fuel thru, I replaced it - Still no fuel to the carbs - Before doing a rebuild on carbs that normally run incredibly well, and even better than my original Limited's Carbs with an airbox, I am reticent to proceed any further with car rebuilds etc without your opinion Thanks for reading this - I hope I can get your thoughts on this -

[@theDaftman]

i got my carburettors all in a box with the bike and they was completely stripped and all messed up. i completely rebuilt them with all new jets and floats emulsion tubes, all new rubbers on both sides of the carburettors, even ultrasonic cleaned them, they come up really good, the bike started first time, the bike revs well and all 4 pipes get hot as they should. my question's is about the "pilot screws" in a lot of videos on KZbin they ask one to take a reading on these by screwing them in fully and count the turns, saying it's vital to put them back where they was, I've replaced mine with all new ones, i had no reference because the carbs was completely stripped, so i set them all the same fully in 2 turns back, question is, how do I set each carb's pilot screws properly. Would this effect cadence as I'm still getting some. This is my first time with these carburettors in fact first time building a rack of 4 carburettor's. Bike is a Honda cb750k DOHC 1979. Hope the above makes sense.

[@nathanaelmaldonado9405]

Great! bro I need you in PR to tune my cb 750k 81 carbs, tired of paying and not working properly😒

[@ClassicRider]

I have this model. One of the biggest issues im running into is heat. I have even gone to 10W50 and my case temp can hit 180 F in 30 minutes. Got any thoughts on this. One question - do you know what this one hits in temp once turned off after use?

[@joeriktd]

The rattle in the background are the worn clutch rubbers

[@patrickreilly988]

Cody, I have a chance to purchase a 1980 cb750f that a previous owner installed a set of cb900f carbs on. Is that a viable swap that can be jetted for the cb750. If so which one of your courses should I purchase to help me clean and jet that set up?

[@danielcervera6025]

excellent video!!!! what would be the point on the vacuum gauge scale that would have to mark well... since there are vacuum gauges with an inHg scale of 20 and others with 50 in the optimal green range... thanks for your answer!!!

[@touchpointpropertymanageme2889]

I would love to watch the master class but your website looks like it's down or I can't get access to it.

[@TheMotorcycleMD]

I’ve been having issues with “MotorcycleMD..com Use “TheMotorcycleMD.com” That one is working perfectly

[@Federicodesalta]

Thanks❤

[@agaba5500]

dang i need this tool

[@SwiftyMcVeigh851]

Hi, and thanks for the video. Where do you source you're rebuilds kits? I often use eBay and look for genuine honda stuff, I was just curious. Also is your master rebuild class in your playlist? I'm pretty well versed with them, but an old dog can learn new tricks. Thank you.

[@senate2042]

The class is on his website.

[@TheMotorcycleMD]

I try to source factory honda parts from factory honda part websites. Like babbitshonda or partzilla. Plenty of sites out there sell big rebuild kits for these bikes. If you are paying 10-20$ per kit then it will likely lack in quality. You can grab the carb course for these models here : www.themotorcyclemd.com/Honda-CB900f-carb-cleaning-workshop-

[@TheMotorcycleMD]

Thanks!

[@BadAssEngineering]

Just bought a NightHawk 750 and it has rough idle and it doesnt run right at low RPMs (under 3,000) Would performing this help? im inclined to think the engine is running too rich since the exhaust has black soot, but i dont know...

[@blipco5]

Great vid. I use a Mercury balancer but it can be a PITA to handle and new Mercury is getting hard to find. I never lend it out.

[@blipco5]

Also with the Mercury, if you take too long, condensation builds up in the tubes and it gets confusing to read.

[@richardmarion978]

Do you ever run a fan on the bikes you work on since they are air cooled?? Just curious, I have a habit of doing this. Another thing is there anyway you could do a video of early 70's model carbs, there different then these and I know they still get synced, but there's a lot more to the adjustment as they don't run the diaphragm and it would be great to see. Thanks keep wrenching

[@csabacsunderlik215]

Whay did you use analog tester? You have a digital Dsynch2...

[@TheMotorcycleMD]

Takes too long to set up honestly. I don't doubt its ability to be accurate. Just a bit of a hassle if you don't have a staged area to plug into. Make that bad boy wifi enabled with a phone app. That would be a game changer.

[@csabacsunderlik215]

@@TheMotorcycleMD Phone screen small for a waves analysis/diagnostic. But we are thinking...

[@TheMotorcycleMD]

@@csabacsunderlik215 Totally understandable. Maybe a no fluff version. Trim the fat, side ways screen shows 2-4-6-8 cylinder bar graphs. Adjust, boom done! 🤷🏻‍♂️

[@ClassicRider]

She looks nice - Do you have the paint codes for the Limited Edition? Thanks !

[@jamesfarrington7434]

Hi I'm trying to get my cb900c running correctly. Yiu seem to be knowledgable was wondering if I could get some ideas. After setting for the winter cold it doesn't want to idle. Idles perfect semi warm it idles perfect. Oporating temp if I rev it it hangs 3-5 grand if I try to drop it down it it quits. Start it back up idles normal until I rev it then it hangs again.

[@bob4bob3bob2bob]

How many jet sizes would you expect to increase, if you changed to a performance exhaust on a Flat 4? Please, and thank you Cody. ( Suzuki GS750 78, standard air box).

[@bob4bob3bob2bob]

Thanks for the uploads. How long would you run an air cooled flat4 before worrying about when it was overheating?

[@TheMotorcycleMD]

Kinda depends on outside temp and if you are talking about the bike running without riding it or moving. Once the bike is warmed up to operating temp, I would not let an air cooled bike sit and idle for more than 15 - 20 minutes without some source of air flowing over it.

[@bob4bob3bob2bob]

@@TheMotorcycleMD Sorry, should have been clear. How long when your are working on tuning the carbs in the workshop?

[@opichocal]

@@bob4bob3bob2bob just put a fan on high in front of the engine or a leaf blower

[@IrishWarCry11]

CB750L 😉

[@tomburdett6639]

👍👍👍😁

[@jesse.jsmall0652]

Ran great and idled great and then I think it sucked something up because with the choke off it’s idling it like three grand 8000 original miles

[@kristinalynn5723]

That looks just like mine! Which still doesn’t charge by the way lol.

[@yobgib1000]

🤟

[@williamknutson6163]

I have the same exact bike and it's running way lean... It'll only run with the choke pulled on...

[@colinhall8998]

Please tell your viewers they are definitely NOT Philips screws, they are JIS screws that require a JIS screwdriver.

[@TheMotorcycleMD]

It’s not that serious man!

[@originalterrorsquad]

How tall are you by the way?