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Fj1100 fuel issues - fuel tap and filler cap

Started by Jemiss, August 23, 2020, 12:26:48 PM

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Jemiss

Hi Everyone
My FJ 1100 has two issues, the fuel tap leaks due to the vac diaphram which I can get a kit to fix. However my filler cap leaks as well. New filler caps do not seem to be a thing for the 1100 so is there a repair kit available? I think one of my worst nightmares is to end up in an accident and then covered in petrol!
84 FJ 1100
85 FJ 1100

Pat Conlon

Hello Jemiss, welcome to the forum.

Fix your petcock, that's most important....don't forget to safety wire the petcock elbow.
http://www.fjowners.com/index.php?topic=3265.0

On your tank cap, you want the cap to let in air as your fuel level drops so as to equalize the pressure.  Without some sort of relief vent, the fuel flow to your carbs will slow to a point of starvation.
Now, that being said, FJ's sold in Califorina, USA had a special fuel tank venting system that prevented fuel vapors from escaping the tank. Those Calif. Models had sealed tank caps. This was an emissions feature not a safety feature. If you have one of these FJ's (Calif Model) and you want to remove the vapor recovery system, all the hoses and charcoal canisters,  you will need to alter your cap to be able let the air pressure equalize in your tank.

In short, I would not worry about a fuel cap that leaks fuel...it also draws in air, which is a good thing.
Fuel leaks from the cap? Not a concern...
I never fill my bike on the center stand.
Reason: If I fill it too full when on the center stand, the fuel will leak out the cap when I put my bike on it's side stand.
I always fill my bike on it's side stand.

Along with the safety wire on the petcock elbow another important point on the early '84-87 FJ's is making sure your fuel line follows the correct route. You can pinch your fuel line and starve your carbs if not...
http://www.fjowners.com/index.php?topic=18286.0

When you get a chance, check in over at the Introductions section and tell us about yourself....

Cheers Laddie!

Pat
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

Jemiss

That was the reason I had taken the tank off!

Your fuel cap should not leak fuel everywhere, if it leaks on the side stand there is a problem! If you have an accident and you are on the underside of your bike and it is leaking fuel all over you there is something wrong and you have a high chance of dying.

I have never had such issues with any other of my bikes, and I do not wish to have it with this one.
84 FJ 1100
85 FJ 1100

Pat Conlon

If your fuel cap leaks fuel when your bike is on its side stand, something's wrong.
You have overfilled your fuel tank.

My point is simply, unless it's a Calif model, the 84/85 FJ1100 's caps are not air tight.
If you hold the tank upside down, fuel will leak out the vented 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

Dads_FJ

Question:  Is it leaking because one of the locking pins unique to the 1100 is broken or missing?  Here's a little write-up I did for the repair of mine.

http://www.fjowners.com/index.php?topic=13921.msg146760#msg146760
John S.

'84 Yamaha FJ1100
'89 Yamaha FJ1200
'92 Yamaha TDM850
'80 BMW R100S/Sidecar
'81 Yamaha IT250(H)
'77 Yamaha IT175(D)
'39 BSA WM20

Jemiss

That thread was exactly the answer I was looking for!
Thank you
84 FJ 1100
85 FJ 1100

Dads_FJ

Quote from: Jemiss on August 25, 2020, 04:55:30 AM
That thread was exactly the answer I was looking for!
Thank you

We got your back!   :good2:
John S.

'84 Yamaha FJ1100
'89 Yamaha FJ1200
'92 Yamaha TDM850
'80 BMW R100S/Sidecar
'81 Yamaha IT250(H)
'77 Yamaha IT175(D)
'39 BSA WM20