Topic: Can I adjust float bowls without removing the carbs?

[Sandy]

Howdy everyone:

My 1969 CB750 has an issue .  The bike starts immediately and runs just fine for a mostly short distance - until one or maybe two of the float bowls empties and then it stutters from what I think is a lack of fuel.  The fuel petcock shows both of the outlets to be flowing fuel perfectly and the tank is clean.  The two fuel lines are new, but I have not yet installed fuel filters.  While removing the bowls is relatively easily, I can see no way to adjust the floats without removing the tiny dowel that holds the float to the carb.  Seems to me that pulling the carbs would be easier, but I thought I would ask and see what the knowledgeable folks know.  Thanks to everyone in advance.

[Johnie]

A little more history on the bike would help. Like have the carbs ever been removed and cleaned? You are correct in that the best way to do the floats is to take the carbs off and do it right. She could be having fuel delivery issues not just because of the floats, but do to dirty carbs. There is a maze of small orfices for fuel and air which could be causing your issue. Once you clean the carbs "entirely" she will run amazing.

[Greggo]

I adjusted the floats on my K0 the other day without removing the carbs.  It is possible if your hands can fit, but reinstalling the float valves and posts is difficult on the inner two.

It does sound like they may be ready for a cleaning..also check the debris screen in your petcock bowl.

[Sandy]

Johnie and Greggo:

Thanks for the responses - I should have mentioned that Mike Nixon did the carbs for me and that they are clean.  The petcock is also new.  Since my mitts are large and I earlier tried to do a float adjustment on #2 with no luck with the pin holding the float and thinking that it only takes about 20 minutes to remove the carbs, I am sure the best way is to remove them and check all the float heights. Thank you for your responses.

[greenjeans]

do a search for clear tube method of checking the floats while you have those carbs out.
That is the most accurate method.

[stewonepot]

Don"t tell Lucky!

[evanphi]

do a search for clear tube method of checking the floats while you have those carbs out.
That is the most accurate method.

But isn't it best to be doing clear tube method with them still on the bike, which is what he wanted in the first place?

[Flyin900]

If Mike Nixon did the carbs recently have you checked with him? He is one of the best in the business with very few who are more knowledgeable on Honda carbs.
Just seems that if you are adjusting something you need to know what the reason is for that adjustment, especially if a carb specialist has done work on them.

[Sandy]

Results and it is all good

I pulled the carbs which was the easiest (for me) way to go.  The problem was #1 had a stuck float needle.  With the carbs on my bench and the float bowls removed I tried to blow air through #3 & 4 - no issues when I held the floats - the air did not flow air when the floats were closed and they flowed air when I opened them.  Different story on #1 & 2 - air would flow when #2 was opened, but not #1.  For some reason the #1 float needle was "stuck" and only minute amounts of fuel could get through.  Pulled the #1 needle and then air flowed perfectly when the floats were opened and nothing flowed when I closed them.  Life is good .  And, please remember that these float needles are metal and cantankerous - they take a bit of "breaking in".

So, the carbs did not need to be removed as #1 is easily accessed.  So are the fuel lines when you remove the tank.  So, pull all four bowls and start huffing and puffing and you just might find what the issue is.

And, as far as Mike Nixon - his work is the best.  He refurbished the carbs on the CB750, the CB1100R and a few others that I have since sold. I have never had an issue with any of his work.

And, just as a bit of information - yanking the carbs on this CB750 is easy.  For those of you who remove carbs on the Honda DOHC's and the CBX's know what I am talking about.  Sure, they are some 13+ years newer, but sooooo difficult to remove and clean.

Thanks to everyone.