Author Topic: Leaking carb question  (Read 734 times)

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Offline andy8190

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Leaking carb question
« on: August 19, 2016, 07:28:20 AM »
cb350f with foam floats for reference of the post

I have done my research on this but wanting some opinions. I have a carb that is leaking but seems to be only when on the side stand. I think it is either:
1. sticking float due to the pivot pin being too small because I made my own using brass shirt hanger.
2. possibly the float not floating like it should
3. bad adjustment of float
4. crack in drain tube

I do not think it is the float valve, it is new. I am going to check the drain tube this weekend for a crack, as well as check the height adjustment on the float again.

What I would like some suggestions on are:
1. Anyone know a source to buy just the pivot pins, or a better way to make my own. If I make my own I would like to be able to buy the part some where local and not have to order online.

2. Is there a proper way to check if the floats are floating correctly?

Offline calj737

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Re: Leaking carb question
« Reply #1 on: August 19, 2016, 09:19:06 AM »
Clear Tube method.

Drain bowl closed to measure height. Motor running to measure fluctuation.
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"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline andy8190

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Re: Leaking carb question
« Reply #2 on: August 19, 2016, 09:45:04 AM »
I can't do the clear tube method bc a couple of my drain screws striped the threads so I had to jb weld them closed

Offline calj737

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Re: Leaking carb question
« Reply #3 on: August 19, 2016, 10:00:14 AM »
You need to replace those bowls then. You have bolloxed yourself  :o
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"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline andy8190

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Re: Leaking carb question
« Reply #4 on: August 19, 2016, 12:58:16 PM »
I don't understand why they are bolloxed? the drain screws are only there for draining. If I have to drain them I just take the whole bowl off. I will agree it is more hassle but I dont want to pay 40 for a bowl

Offline BobbyR

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Re: Leaking carb question
« Reply #5 on: August 19, 2016, 01:09:15 PM »
Well you did limit your options. The clear tube method is the best for checking fuel height in the bowl. If you find a cracked tube inside, PUT DOWN THE JB WELD.  You can clean them and use solder. Solder is a permanent fix. Forget plastic tubing and any other crap you may be told. Just plain solder.
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Offline Flyin900

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Re: Leaking carb question
« Reply #6 on: August 19, 2016, 01:28:44 PM »
With all the little fixs you have done there is no wonder you are having issues with the carbs. Since these use a metal on metal system for the seal in the float needle assy they need to be bang on with correct alignment and fit.

Find the correct parts as suggested with replacement bowls and correct float pins. Ensure the floats are correctly aligned in all axis and not twisted and then set to the proper height per the FSM.

Aftermarket kits are usually the worst for leaking and best to use the stock Honda ones if still good and it not buy replacement OEM Honda for the easiest fix.
Common sense.....isn't so common!

1966 CL77 - 305cc - Gentleman's Scrambler
1967 CL175K0 - Scrambler #802 engine
1972 CB350F - Candy Bacchus Olive - Super Sport
1973 CB350F - Flake Matador Red - Super Sport
1975 CB400F - Parakeet Yellow - Super Sport
1976 CB400F - Varnish Blue - Super Sport
1976 GL1000 - Goldwing Standard
1978 CB550K - Super Sport
1981 GL1100 - Goldwing Standard
1982 CM450A - Hondamatic
1982 CB900C - Custom
1983 CX650E - Eurosport
1983 CB1000C - Custom X 2 Bikes now - both restored
1983 CB1100F - Super Sport - Pristine example
1984 GL1200 - Goldwing Standard

Offline andy8190

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Re: Leaking carb question
« Reply #7 on: August 19, 2016, 02:32:21 PM »
The only problem I have with float pins is that you can't buy just the pin

Offline Flyin900

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Re: Leaking carb question
« Reply #8 on: August 19, 2016, 07:56:00 PM »
Harisuluv on this site may have some parts available, as he is a carb specialist/rebuilder based in the US.

I have done numerous CB350/400/550 carbs and they need to be on spec and with good floats and needle valve assemblies, or they will always leak a little from one or two carbs.

I am based in Canada, yet if you are really stuck for parts I can sell you a couple of bowls and float pins I think. Would just need to know the bowl positions and check my parts stock.
« Last Edit: August 20, 2016, 03:46:17 AM by Flyin900 »
Common sense.....isn't so common!

1966 CL77 - 305cc - Gentleman's Scrambler
1967 CL175K0 - Scrambler #802 engine
1972 CB350F - Candy Bacchus Olive - Super Sport
1973 CB350F - Flake Matador Red - Super Sport
1975 CB400F - Parakeet Yellow - Super Sport
1976 CB400F - Varnish Blue - Super Sport
1976 GL1000 - Goldwing Standard
1978 CB550K - Super Sport
1981 GL1100 - Goldwing Standard
1982 CM450A - Hondamatic
1982 CB900C - Custom
1983 CX650E - Eurosport
1983 CB1000C - Custom X 2 Bikes now - both restored
1983 CB1100F - Super Sport - Pristine example
1984 GL1200 - Goldwing Standard