« previous next »
Pages: [1]   Go Down

Author Topic: Leaking fuel.. Sometimes.  (Read 1187 times)

0 Members and 1 Guest are viewing this topic.

Offline Dimitri13

  • Not a
  • Master
  • *****
  • Posts: 1,603
  • 1974 CB550K
Leaking fuel.. Sometimes.
« on: March 14, 2012, 10:55:58 AM »
It's happened twice in a few months, but most of the time when I leave my petcock on (accidentally) onvernight, no fuel will leak out. But the first time it happened a few months ago, it nearly emptied the tank. Today it happened and it dumped about a pint. First time it was on reserve, and this time it was on on. By the time I saw it, all the fuel overflow tubes were dry, so it must have only happened for a short time and was not continuous.

I'm stumped because I leave my petcock on while I'm at work 8+ hours/day and I've never had a problem. It only happens when it's in my garage.

Bike is a 550k0, carbs are 069A, carbs were rebuilt four months ago, cracks in overflow tubes repaired.
« Last Edit: March 14, 2012, 10:57:32 AM by Dimitri13 »
Logged

Offline LesterPiglet

  • Old Timer
  • ******
  • Posts: 4,045
  • 1977 CB550F2
Re: Leaking fuel.. Sometimes.
« Reply #1 on: March 14, 2012, 10:57:24 AM »
When you park at work is it on the flat?
Logged
'Then' and 'than' are completely different words and have completely different meanings. Same with 'of' and 'have'. Set and sit. There, their and they're. Draw and drawer. Could care less/couldn't care less. Bought/brought FFS.


Les Ross.            Certified by a Professional

Offline Dimitri13

  • Not a
  • Master
  • *****
  • Posts: 1,603
  • 1974 CB550K
Re: Leaking fuel.. Sometimes.
« Reply #2 on: March 14, 2012, 10:59:16 AM »
Yes, it's flat at work and flat in the garage. I always park it on the center stand in my garage, and about 50/50 side/center at work.
Logged

bollingball

  • Guest
Re: Leaking fuel.. Sometimes.
« Reply #3 on: March 14, 2012, 11:29:45 AM »
Forget about where it is at and fix it. Then shut the valve off ALL the time

Ken
Logged

Offline flybox1

  • My wife thinks I'm a
  • Really Old Timer ...
  • *******
  • Posts: 14,289
Re: Leaking fuel.. Sometimes.
« Reply #4 on: March 14, 2012, 11:30:56 AM »
sounds like your bike has performance anxiety when in public  ;D

you might want to crack open those carbs again. check float height, float valve op, and standpipes for leaks.

Logged
'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 MJL

  • Don't listen to me, I'm no
  • Expert
  • ****
  • Posts: 1,162
  • Oh hell, what's one more bike?
Re: Leaking fuel.. Sometimes.
« Reply #5 on: March 14, 2012, 12:38:33 PM »
My 750 leaks through the #4 carb sometimes. I think the float catches on something in the bowl and holds the needle open. I can shake the bike and it'll stop. I just make sure to keep my petcock off.
Logged
No matter how fast or how far I rode, I couldn't leave her memory behind.

Offline Duanob

  • Bold Timer
  • Old Timer
  • ******
  • Posts: 4,019
  • Gotcha!
Re: Leaking fuel.. Sometimes.
« Reply #6 on: March 14, 2012, 01:39:17 PM »
My guess is crud in your float jets. Not a lot just enough to keep them ffrom closing all the way every now and then. When the bike is running the crud will flow with the gas into the bowl but new crud will make it's way in eventually. The best fix is clean your tank and tap real good but just keeping the tap closed when not in use will work fine too.
Logged
"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?

  __o
_- \_<,
(*) /' (*)

Offline TwoTired

  • Really Old Timer ...
  • *******
  • Posts: 21,802
Re: Leaking fuel.. Sometimes.
« Reply #7 on: March 14, 2012, 02:09:24 PM »
How clean is your fuel supply?
what filters?
Logged
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline cameron

  • Hot Shot
  • ***
  • Posts: 558
Re: Leaking fuel.. Sometimes.
« Reply #8 on: March 14, 2012, 02:13:34 PM »
Quote from: Dimitri13 on March 14, 2012, 10:55:58 AM
Bike is a 550k0, carbs are 069A, carbs were rebuilt four months ago, cracks in overflow tubes repaired.

Did it leak before this "repair"?
And now only some of the time?
Logged
1976 CB550F
Pages: [1]   Go Up
« previous next »