Author Topic: gas leaking everywhere!  (Read 1534 times)

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Offline 75 super sport

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gas leaking everywhere!
« on: May 13, 2015, 09:42:03 PM »
Fired the bike up for the first time, gas leaking from everywhere. Coming out of the fitting that shares fuel with 1&2 and 3&4. Pouring out of #3 as well. Had them rebuilt last year but that sat around until now. Not sure what to do. Rebuild them again? Any suggestions on what may be going on?
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Offline Davez134

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Re: gas leaking everywhere!
« Reply #1 on: May 13, 2015, 10:04:54 PM »
The fittings have O-rings, replace. Float may be stuck on #3 or float needle/seat may be worn or have debris in there. Try this first before just rebuilding everything.

Offline 75 super sport

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Re: gas leaking everywhere!
« Reply #2 on: May 13, 2015, 10:12:01 PM »
Do the o rings for the fittings come in a rebuild kit? The kits are fairly cheap
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Offline Davez134

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Re: gas leaking everywhere!
« Reply #3 on: May 13, 2015, 10:38:03 PM »
Without looking at the specific kit, I couldn't tell ya, but usually no. There are 4 rings on each fitting, you will need 8 total, and I believe they are 2mm thick x8mm diameter. Waaaay cheaper than a complete rebuild kit.

Offline 75 super sport

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Re: gas leaking everywhere!
« Reply #4 on: May 14, 2015, 04:27:49 AM »
Do you know where I can find them?
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Offline Davez134

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Re: gas leaking everywhere!
« Reply #5 on: May 14, 2015, 04:51:37 AM »
Harbor freight oring kits, any hardware store that sells orings. Not hard to find.

Offline 70CB750

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Re: gas leaking everywhere!
« Reply #6 on: May 14, 2015, 04:57:00 AM »
I took mine to Lowe's and found the right size of o-rings.   

The HF o-ring kit is a great thing to have too.
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Offline Johnie

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Re: gas leaking everywhere!
« Reply #7 on: May 14, 2015, 05:24:09 AM »
NAPA o-ring part number 727-2605. The only way to replace those is to separate the carbs which why some people take short cuts and don't change them out.
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Offline flybox1

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Re: gas leaking everywhere!
« Reply #8 on: May 14, 2015, 06:55:31 AM »
As these orings only contact fuel, and are not exposed to excessive heat, at a minimum, use BUNA-N, orings.
VITON(FKM) are also fuel resistant, but have a higher heat rating.
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Offline 75 super sport

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Re: gas leaking everywhere!
« Reply #9 on: May 14, 2015, 07:10:22 AM »
So the ones from Napa, are they ok to use?
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Offline flybox1

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Re: gas leaking everywhere!
« Reply #10 on: May 14, 2015, 08:01:26 AM »
So the ones from Napa, are they ok to use?
i dont work at napa, so i dont know.  guess youre going to have to ask  :P
use buna-n  or viton, only....
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline Duanob

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Re: gas leaking everywhere!
« Reply #11 on: May 14, 2015, 08:57:17 AM »
Am I the only one that doesn't know what bike he has? 75 all three sizes came in Supersport models. I would just buy the Honda gasket carb kits for $15 each. Then you know you will have all gaskets and o-rings made of quality material in the perfect sizes. They are readily available for the 550F carbs, probably for the 750F, not sure about the 400F.

Most guys will tell you not to sepearate the carbs but it's not rocket science and I always feel better knowing the fuel 'T' orings have been changed. Plus its easier to change out the fuel lines when the carbs are seperate and the fuel T removed.
« Last Edit: May 14, 2015, 08:58:58 AM by Duanob »
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Offline 75 super sport

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Re: gas leaking everywhere!
« Reply #12 on: May 14, 2015, 09:54:08 AM »
75 cb750f. I bought 4 carb rebuild kits and a bunch of Vinton 8mm x 2mm gaskets for the "t"s. Should work eh?
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Offline Duanob

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Re: gas leaking everywhere!
« Reply #13 on: May 14, 2015, 10:00:46 AM »
75 cb750f. I bought 4 carb rebuild kits and a bunch of Vinton 8mm x 2mm gaskets for the "t"s. Should work eh?

The kits didn't come with the T orings? Strange.
"Just because you flush a boatload of money down the toilet, doesn't make the toilet worth more",  My Stepfather the Unknown Poet

1974 CB360T
1976 CB550K2 Resurrected
1976 CB550F2 Barn Find
1979 CX500 VG "HONDA-GUZZI"
2007 Moto Guzzi Breva 750ie
2015 BMW F700GS
Another 1976 CB550K Cafe?

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_- \_<,
(*) /' (*)

Offline 75 super sport

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Re: gas leaking everywhere!
« Reply #14 on: May 14, 2015, 10:14:23 AM »
No I don't believe so
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Offline Johnie

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Re: gas leaking everywhere!
« Reply #15 on: May 14, 2015, 11:18:46 AM »
I have only used the NAPA o-rings. My KO has had them in now for 9 years. They will be fine.
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline Bodi

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Re: gas leaking everywhere!
« Reply #16 on: May 15, 2015, 08:15:19 AM »
The Honda OEM carb gasket kits come with the crossover o-rings. Not as cheap as aftermarket kits, or just getting o-rings locally. You do get the cap gasket and a bowl gasket o-ring as well. These OEM parts are not 100% ethanol resistant as of the last kits I bought, mid 2013.

Offline Duke McDukiedook

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Re: gas leaking everywhere!
« Reply #17 on: May 15, 2015, 09:25:19 AM »
Go with Viton if you can.
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Offline 75 super sport

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Re: gas leaking everywhere!
« Reply #18 on: May 15, 2015, 12:19:56 PM »
I got some Viton o rings on the way :) so what would make the carb fill up and over flow out of the intake side of the carb and flood into the motor? Brand new top end with 836 big bore and I really do not want to harm the motor!
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Offline Duke McDukiedook

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Re: gas leaking everywhere!
« Reply #19 on: May 15, 2015, 12:42:33 PM »
Leaky float valves. I just shut off my petcock when I park it for more than 5 minutes.
"Well, Mr. Carpetbagger. We got somethin' in this territory called the Missouri boat ride."   Josey Wales

"It's Baltimore, gentlemen. The gods will not save you." Ervin Burrell

CB750 K3 crat | (2) 1986 VFR750F