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Leaking Fuel for the gazillionth time

Started by FJ1200W, February 28, 2017, 06:29:54 PM

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FJ1200W

Bikes parked, leaks fuel -

I replaced the float valves, blah blah blah, even installed a cute little shut off valve -



Came home the other day, parked the bike after running the fuel out of the bowls.

Next day, it leaked, a lot.

Then I thought about it - I just filled up.

I bet I have been overfilling the tank - and when I park it hot, even with the fuel shut off, the fuel expands enough from the heat to overflow from some vent tube -

Could be true - thoughts?

Thanks in advance
Steve
Columbia, Missouri
USA

ribbert

Well, if you have a shut off valve (and assuming you have the off/on position correct, if it's a valve and not a tap, the picture shows it "on") it can only be coming out the overflow and yes parking it hot and full is likely to make this happen. Particularly if you fill it with the bike vertical then park it on the side stand.

A shut off valve is a good idea but a manual unit under the side cover seems a bit cumbersome and over time you get lazy if it's not convenient and stop using it, or, break the tabs off the side covers from constant removal. You could put a solenoid valve in there wired to the ignition.

Easiest way to diagnose your problem would be to not fill it right up, park it and see what happens.

I'm in the habit of never parking my bike full, but only because of the FJ's propensity to leak fuel past the fuel pump and a full tank increases the head pressure and therefore the likelihood of that happening.

IMO

Noel
"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

Pat Conlon

Also, I do not fill my bike on the center stand. When parked on the side stand fuel can leak out the cap.

No big deal on the '86+ FJ's with the recessed cap and drain hose, but absolutely devestating to the paint on the early '84/85's with the non recessed cap.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

mark1969

I kept getting fuel overflows - replaced the needle valves, didn't work. Eventually I replaced the o-rings on all the connecting tubes between carbs and it has been fine since. I put that down to the fuel pump still delivering fuel as there was not enough pressure build up due to the defunct o-rings?

I don't know, but it worked..


bikemad

It's good to know that I'm not the only guy having these problems!
I'm about to put a shut off valve in the system that I'll activate when the bikes parked up.
I've had the carbs apart and nothing seems suss.
Mines a '89 model 3cv.
FJ1100
FJ1200 3cv

CutterBill

Never Slow Down, Never Grow Old.

Current Stable:                                                     
FJ1100                                              
FJ1200 (4)
1999 Yamaha WR400 (street-legal)
2015 Super Tenere
2002 Honda Goldwing

ELIMINATOR

I tried tapping the offending carb with anything that would reach the float bowl, as suggested on this site before. I cured it by blowing down the offending overflow pipe when the bike was running.
BMW 1150GS
Moto Guzzi California 3

FJmonkey

Drain the offending carb, then fill it back up by starting the engine. Fresh fuel will flush the crud when the float is wide open. Works every time.  :dance2:
The glass is not half full, it was engineered with a 2X safety factor.

'86 Ambulance - Bent frame, cracked case, due for an overhaul
'89 Stormy Blue - Suits my Dark Side

Zwartie

This was my solution:



You can get more detailed info on this thread: http://www.fjowners.com/index.php?topic=16529.msg168451#msg168451

As others have mentioned, verify if it is the fuel tank overflow or one of the carbs. The shut-off solenoid won't do anything for the tank overflow but it should prevent or at least minimize the leakage should one of the carbs decide to spew.

Zwartie
Ben Zwart
London, ON
1992 FJ1200
1977 KZ200