Leaky carbs

[AndyD]

Hi all,
I know it's a common issue the carbs leaking through the overflow and sure enough the poor old gal suffers this indignity as well after refurbing the carbs.
Everything cleaned and reassembled fine with new O rings etc.
Spent a few happy hours setting the float levels having read many topics on here - ended up using the method with carbs on side and very slightest pressure on the float pin.
First time on test she dribbled happily so took apart again and re-cleaned the float pins etc. and checked float levels again.
Put back on test and again 2 carbs started dripping straight away - 1 quite a constant flow, the other a slower drip.
I'm guessing this means the float pins / valve may need replacing so i wondered what opinions were on different replacements available (trying to keep spend down so cheaper the better!).
Any views welcome
Cheers,
Andy

[Johnwebley]

Could be as simple as sticking float

Give each of the leaky carbs at solid tap with a plastic screwdriver handle.
and when we get chance to ride them for longer.
Put some Redex cleaner in the tank.

Help to keep the carbs free

Sent from my SM-A750FN using Tapatalk

[TrickyMicky]

Before spending any dosh on parts, one problem which bugged me a couple of times is the spindle pins which the floats pivot on. They can get gunged up with infrequent use, so remove pins and very gently give them a polish with some VERY fine wet & dry, and see if that helps. Stay healthy, Mick.

[florence]

might sound crazy but carefully inspect the brass pipe in the float chamber.  I have had different Hondas develop a hairline crack in this tube.  No matter what your float height, petrol will leak out.  It's very easily missed and makes one suspect the float or the valve.  Also make sure the floats float and are not filling up with petrol.

[AndyD]

Thanks all
I tried tapping bowls but no effect
Took pins and floats off and checked all move freely
Checked the brass tubes and all seem fine
Suspect the float valve so will try swapping the fast leaking one to a different carb so hopefully will show if that’s the problem.
Cheers
Andy

[andut]

Andy,. Give the valve and seat a good clean and polish.  I use a cotton bud and a bit of Solvol to get the seat clean.


Andy

[taysidedragon]

You can check the brass overflow tubes before fitting bowls onto carbs.
Half fill the bowl over a catchtray or bowl. If the tube leaks it will  drip. Sometimes it can creep between the tube and the alloy bowl.

[Oggers]

Another vote for floats not floating for me. I had a GS550 whose floats did not rise to the occassion and it spewed forth from the drains  every time it came to a standstill. Personally I would check them out and fix/replace if required.

[Nurse Julie]

I would start with float needle and seat and then put all floats in a bowl of water and make sure firstly they all float and secondly they all float at the same level.

[billywingnut]

When I did my restoration I decided to buy new service kits, I also checked each float bowl before re assembly for leaks as mentioned  earlier. It has leaked on only one occasion after being stored for a while, a gentle tap stopped it and it hasn't happened since in over a year.

[florence]

I think modern petrol is causing problems.  My CB350 has brass floats, one of them developed a hole, it was tiny but when I pressed the area the whole thing fell to bits on one side.  Also, I had a float bowl holed and float bowl tube split.  All on the same bike, which is why I have put on some AMALs I had lying around.  Back when I rode the bike, the original carbs were always temperamental, sticking diaphragm/sliders, so will be interesting to see what it is like with slide carbs.  Sorry, I'm digressing.
 

[SeanFD]

I would start with float needle and seat and then put all floats in a bowl of water and make sure firstly they all float and secondly they all float at the same level.

Also try holding them under the water - like looking for a puncture - in case the hole/crack is at the top. When you take them out give them a shake and listen for fluid inside.

[AndyD]

Again thanks everyone
Plenty of things to check when I get away from work today.
I didn't know that the floats were hollow on these so will check them in water.
Also will clean the float valves again just to be sure and the brass pipe for leaks

If all else fails are there any good / bad recommendations on repair parts - eBay has quite a few offering from around the world varying enormously in cost and contents.
On the GS1000s the strong recommendation was never use anything except original due to quality issues - is that the same fro these bikes?

Will update after the next round

Cheers,
Andy

[H2Eric]

This problem sounds very familiar. If you have to replace the float needles and seats use genuine parts, others are pretty dire from my experience. As Julie says check that the floats float and they are all at the same level, mine didn't. I replaced the float needles and floats on my 350F and all is now tickety-boo and leak free. I had a similar problem with brass floats on an H2 which sank i.e. full of holes and full of petrol. Allens Performance came to the rescue with 3 new floats, problem solved and that was long before ethanol problems.

Cheers all

Eric

[taysidedragon]

I bought rebuild kits from David Silver for mine and they work just fine. They are Keyster kits that sometimes get bad reports. Maybe there are fakes on the market so buy from a reputable dealer.