leaking carb

[andrew]

I have a 77 CB750.  One of my carbs is leaking from one of the tubes that connect one carb to the other.  i believe it is one of the fuel tubes.  i noticed on the schematic that there are o rings on the end of each tube.  that would seem to be the culprit.  does anyone have an opinion, and are those o rings easy enough to replace or do i need someone who is good with carbs to do it?

I thought the leak was coming from the float bowl and i replaced the float bowl gasket.  the leak is coming from the tube right above the float bowl.  has anyone else encountered this problem?

[cdaiscool]

You can split the carb bank to get to the o-ring. It's possible it was compromised somehow, sure. I would clean it, put baby powder on the area, and see if it leaks. If it does, then pull the carbs, split the bank, and replace the tube's o-ring.

[Lucky 1]

IT seems like you still are not sure where the leak is coming from.

If the O ring on that interconnecting fuel tube is leaking
it means complete disassembly of the carbs.

That is out of your league.
If it is not done right you can end up breaking other parts.
Also during the tear down of the carbs other problems could be encountered.
Then you may need other parts.

Try to really make sure where the leak is coming from
Like i would want to hear you say you absolutely know where the leak is coming from.

HAve Harrisluv1 on Ebay rebuild them for you .He does a great job for the price.
Remember you are working on parts that are 33 years old.

I just took apart a set of 1972 carbs and the bronze bushings in the throttle shafts
had corrosion damage and the steel shaft had some damage from being next to the bronze bushing.
One broke screw so far. Stuff like that. You have to go find all of those parts.

[shinyribs]

Nothing is out of anyone's league.  Anyone can ask and learn.

[Half-Caf]

shinyribs wrote

Nothing is out of anyone's league.  Anyone can ask and learn.

What about girls?

[shinyribs]

I cant give advice on girls...i'm still heavily confounded by them.

[Piute]

   Hey Andrew,My key-top carbs leaked ,I thought was the bowl gasket(again),But was the rubber tube(between 2+3),that connects the accelerator pump fuel.
   So ,I cut off a peace from the over flow tubes , squeezed(made tighter) the wire clamp a bit and put on hasn't leak so far.But this proved the pump was working

[andrew]

Its definitely coming from the the tube right above the float bowl...looks like a complete teardown which i will not take on...sucks because i need to sell the bike cause i just bought a boat...thanks for all of the advice

[Re-run]

The orings are easy to replace. You will need to pull the carbs off and then remove the mounting plate.
Open the tops up and take out the screws on #3 and 4 and you should see the carbs move and you should be able to slide them a bit. Watch your choke linkage so you can see how it goes back together if it comes apart. You just need to be able to get the tube out so things do not need to be torn down completely.

[andrew]

I tried to pull the mounting plate off by taking out the screws, but the plate wouldnt budge...is there a step i am missing in taking off the mounting plate?

[Re-run]

If it has been a while, you might need to whack it with a screwdriver handle. There are 8 screws to remove so make sure you got them all.
Do you have the manual to review?

[andrew]

Yeah i didn't want to hit it without being sure...no manual just some basic mechanical skills...just hope i don't forget how to put the thing back together once i tear it apart

[robs750]

What year is your bike?

The philips screws can be hard to remove.Buy a hand held impact driver that you hit with a hammer.Harbor Freight has them i think.

The first time I worked on CB750 carbs was four weeks ago,helping my son with his '82 CB750K.
We completley tore the carbs apart.Looked kind of scary at first but very easy now because we had starting issues and went back into the carbs several times since thinking that they were the problem.
After doing a compression check,we found the  cyl's hitting at 40,60,40,120.So a valve clearance check shows that four of the exhaust valves are at .002-.003 and the other four will not accept a .0015" gauge.
The intakes are at .004-.005".
I'm waiting for the shim tool I ordered so I can remove the tight shims and grind them to get .005" clearance.Hopefully the adjustment will fix the low compression.