leaking carbs

[Armor77]

Hello, everyone! I'm new to the forum and new to motorcycling.I have a 1980 CB750 Custom that I bought earlier this year.  I've noticed that fuel is leaking from the carbs and even after the repair shop told me they fixed the problem.  I'm debating taking it back to the shop or doing the work myself.  Anyone else have this problem before?

[LukeM]

Try and find the source of the leak: is it coming from the overflow tubes at the bottom, or is it coming from the connection between the float bowl(s) and the carb body?  If it's coming out of the overflow, it's most likely an issue with the float needle valves inside the carb bowl.  They could be dirty or worn and need to be replaced.

If it's leaking where the carb bowl meets the body, that's most likely a carb bowl gasket.  You can get these off of EBay, one of the shops mentioned on this forum, or Mr. Dealer.  I replaced mine on my Shadow.  Had to buy 4 of them, and they were $7 each.  Not a bad deal.

Good luck, and keep us informed.  Welcome to the forum.
Luke M

[Piute]

Ya-no LukeM reading over these problems with carb leaking witch is a new one every week it seems may be next,Think we could have a permanet Carb sectionThanks every-one for the GOOD Info >>>piute<<<N>>>Judose<<<

[TOOLS1]

That would make too much sense. What would be the fun in that?
TOOLS

[awesome sauce]

i too own a 1980 cb 750 c and im having the exact same problem.  thanks to tools and some of the other members on this site ive been able to do all my own work on the bike.  what i would recommend first find out where the leak is coming from. my issue had be leaking from the overflows. if its the overflows try tapping on the float bowls with a screwdriver. if the float needles are just guncked up from bad gas the leak should stop. at this point your gonna have to pull your carb and clean it out.  not that big a deal.  if the leak keeps going your gonna have to pull the carb anyway to check the float needles to see if there damaged or if the floats themselves are damaged.  my float needles are marked up im replacing em as soon as my bike shop gets em in!  
   my advice would be to take it back to the mechanic, you paid for a problem to be fixed get your moneys worth.  But after that say good by to the mechanic and embrace the madness that is motorcycles! (that being said i am getting my bike inspected by a mechanic before i put her on the road;-)

[TOOLS1]

Welcome to the forum. When people like, you join. It makes my life, so much easier.
TOOLS

[mitchell.lee.miller]

Hello!

I'm having the same issue (leak on carb three n four), except I have cleaned the needles, the floats are working, and the release tubes (proper term?) are clear and free.  I think it is where the fuel comes in from the tank, the gas leaks right from the split between the two carbs...I'm pretty sure.  Is there an easy way to pull the two carbs apart and get in there and replace a gasket or ring or something? Help?

[I want to get on those back roads again quick while the weather is getting warmer and warmer]


77 CB750K

[TOOLS1]

Unfortunately on a 77 CB 750 with keyhole carbs, there is no easy way to split them to replace the o-rings.
TOOLS

[mitchell.lee.miller]

Okay, so what do I do, I refuse to take it in--plus I want to learn how to do this.

[Piute]

                                         I know it's hard  
                  But pull it and go over it all again and again till it's right
               Being stuck on rthe side of the road is not going to be good
                          Lets keep the work in are shops doing it are selves

                SORRY ,use a flashlight and find that leak ,take off tank set between step (up high) on 6' ladder  with longer hose pf course(couple bucks)............NOW you can SEE.

[TOOLS1]

What Piute said. It's not easy, but can be done. Take lots of pictures before, and during disassembley. If, you have question/problems just ask, were here to help.
TOOLS

[mitchell.lee.miller]

Alright!  I'll try it.  I thank y'all for your moral support and the good advice.  I also just want to put out there that the CB750K is the best motorcycle, the best hobby is tinkering with a good motorcycle and tooling around on it.  

I just noticed as I was looking at my air filter housing, it says CB750F on it!  Wrong part?  Any good ideas for finding an air filter casing/housing and other assorted parts?  Ebay...meh...

Thanks everyone!
1977 CB750K ~ Roxanne

[TOOLS1]

The air box's are all the same on the SOHC bikes. Wonder about the F though.
TOOLS

[shinyribs]

I have the stock airbox off of my '76 Super Sport. If you need one let me know. I'll sell it for $20+shipping

[Piute]

   The air box's are all the same on the SOHC bikes. Wonder about the F though.
TOOLS                            
                                                             

                       Wondered this myself,will post some pictures of mounting area's less some-?
                    I NEED a different box has a stripped bolt holder in plastic,
                    1 of the only "BAD" ideas I've noticed,Some bone-head over tightened.

[mitchell.lee.miller]

Took the carburetors out and separated them, and put new O-rings in(decided to do the other side while I was at it.  A few bucks and couple of hours of tinkering and I was riding!  Fun stuff, I used the advice you all gave, latter and long hose and took a bunch of pictures, it all helped so thanks again.  It started on the second kick.  What a fun Sunday!!

The filter box was sold to me via ebay as CB750 box and it says on it,"HM  CB750F" on it..dare I try to post a picture..

[TOOLS1]

Good job I thought, you were the guy with the 77. I just noticed that, you were a different poster. Your carbs are the round tops. I really like the round tops. They are some of the easiest carbs to work on.
TOOLS

[shinyribs]

Glad you got it going. The first ride on a new bike is always a blast!