Topic: 1978 Honda cb750k ( carbs)

[drmeloh]

Im planning to rebuild  the carbs on my bike. Does anybody  have a link for a complete/clear digram of how the carbs are assembled, just to have more reference.
also, how is the proper way to adjust the main jets if individual air filters are used?

[lucky]

Im planning to rebuild  the carbs on my bike. Does anybody  have a link for a complete/clear digram of how the carbs are assembled, just to have more reference.
also, how is the proper way to adjust the main jets if individual air filters are used?

You cannot adjust main jets. You can only change main jets.
Get a Honda workshop manual.

You do not really have to take them all apart.
Just clean them and blow the passageways out with carb cleaner. Protect your eyes!!!!
You will need to REPLACE  the float needles and set the floats.

[BrockSamson]

The google search bar on the left is very useful, the search at the top right is broken. 

Look for posts on the PD carbs or 77/78k 750s.  A person on this forum "Lucky" has been compiling information on different air/exhaust combinations on the 750s and what mains/pilots/etc are used and what results people are getting.

The stock carbs for the CB750s are not very fond of individual pod filters.  It is really happy with the stock airbox.  If you are looking for an alternative to that use the search and look for the "Antipod" created by Tintop.  You can go with pods and its been done a lot, but be prepared to have your hands full.  You will definitely have to up your main and pilot jets.

By the way welcome to the forum.  Also, you will find people are hesitant to help unless you provide every detail about your bike.  Year/Model/Miles, air intake modifications, exhaust modifications, electronic ignition or points, if its been sitting or running, plug chop information... all that good stuff.  It also helps if you show that you have attempted to use the search.  Last but not least we love pictures.

Good luck!

[flybox1]

take pictures as you take them apart. get a copy of the shop manual.
take one apart at a time.
if you have the PD42 carbs with the accel pump, go here for some help.
http://forums.sohc4.net/index.php?topic=76757.75

[harisuluv]

I'm sure if you use the search function you can find out all you will ever need to know about them.  If you get stuck, you can call me if you have a quick question, always willing to help out other forum members.  My number is in my sig.

[bollingball]

Im planning to rebuild  the carbs on my bike. Does anybody  have a link for a complete/clear digram of how the carbs are assembled, just to have more reference.
also, how is the proper way to adjust the main jets if individual air filters are used?

You cannot adjust main jets. You can only change main jets.
Get a Honda workshop manual.

You do not really have to take them all apart.Just clean them and blow the passageways out with carb cleaner. Protect your eyes!!!!
You will need to REPLACE  the float needles and set the floats.

Lucky  If I may (drm) I think Lucky means you do not have to take the rack apart. Leave them hook together but take the top and bottom off to clean The only reason to take the rack apart is if the bushings on the throttle or choke need work or the cross pipes need work. The main thing on these carbs is to clean the accelerator pump so it works as it should. Also in the Honda shop manual it says the slow jets can not be removed but they can and must be. more on this when you get to breaking them down. Lots of help and post here. I don't think you will find a better site for help on these SOHC bikes.

Ken

[750K]

Take pics of them before you start pulling the jets and needles etc out, I always try and keep things in groups. As in keep the parts from carb #1 together while you're cleaning them. I either put each carbs jets and needle etc in its own container and clean one set at a time, while I'm soaking the whole rack. Keeps things organized and on track.

[cookindaddy]

One thing you may have trouble with on re-assembly (I did) is the hookup of the two halves of the throttle shaft and the two springs. They are shown in the diagram on the assembly axis but they end up together in an interesting way. The way the springs hook over the hooks on the two ends of the two parts of the shaft was quite a puzzle for me. Fortunately, I had another carb to look at. As was suggested, pictures will help you generally, but this particular thing you might pay extra attention to as you take it apart.

Be methodical and all will go well for your rebuild.

George

[drmeloh]

thanks every advise.. When i bought my bike (2-3 months ago/everything is stock except for some lights) it turned perfectly but after a while, it didnt want to. The precious owner had cleaned the carbs but i decided to rebuild them. I been doing research, about the carbs (how to disassemble, and assemble them), quiet easy in a way.
since i have single pod filters, I found out that i have to adjust the jet needle and what not to maintain a good ratio of air and gas. too what measurements?
the floats are to be   26mm right?

[bollingball]

the floats are to be   26mm right?

No not even close where did you read that?  12.5 or 3 to 4mm below the bowl gasket.

Have you downloaded the Honda manual?


Ken

[bollingball]

"it turned perfectly but after a while, it didnt want to".
Can you explain this a little better?

The precious owner
I hope this is a girl There is a spell checker on here.

Ken

[drmeloh]

sorry  , spell check: "it turned on perfectly at first".   & "Previous owner"

( this is my first bike, so i don't know much about them that's why I'm asking a lot of question to catch up)
I've read it somewhere. it said it was 26mm from the "lip" or top of the bowl to the top of the float. I do have the Manuel, i have to double check it.
but since i have single pods, i would have to adjust that as well right?

[harisuluv]

26mm is for earlier carbs

[bollingball]

Maybe not
When you look at the manual Scroll down to about page 247 That is where the 1977 supplement starts
Just kidding about the spell check I am the worst.

Ken

[flybox1]

The fastest way to get your floats set is to get them to be the same height as the top of the pilot jet. Its easy to see as the pilot jet is right between each set of floats.
done.
easy.

[bollingball]

I like to use the clear tube method on these carbs put it right where the drain tubes are and run it up the side of the carb body and then open the drain then you know exactly where the fuel level is.
edit I think the 77 is the same as the 78. That is what I have

Ken