Leaking petcock, o-ring will not seal

[eeshed]

Dear community,
My 1985 FJ1100 has a fuel leak from the petcock. I think the leak comes from the o-ring fitting of the pipe that comes out of the shut-off.  When I shut off the petcock the leak stops. Any ideas how to fix that? My mechanic suggested: a) find a used replacement petcock. b) find a brass threaded nipple, and tapper thread the petcock to fit the nipple.

Does any one have experience with fixing this problem? Any suggestions?

Best regards,

E

[Dads_FJ]

A used one will probably have issues as well.  I would recommend a new one.  http://rpmracingca.com/proddetail.asp?prod=M%2FC%3A84-85Petcock

[fintip]

My solution to this problem ('86, so similar enough) was to put a small rubber 'washer' that I found at a local hardware store behind the spring. First I replaced the plunger o-ring, of course, but that didn't fix my problem. No leak after shimming the spring, though!

However, I shortly thereafter developed the 'failing vacuum' 'monkey-itis' syndrom, where my petcock

1. Will not deliver enough fuel if I ride at 120 mph for extended jaunts (not a huge problem)
2. Will not deliver enough fuel if the tank has less than 1.5-2 gallons in it (kind of a pain, but I've been living with it like this for months now, just refill  at the 125 mile mark on my trip meter to be safe).

The knowledge I've collected on petcocks so far is here, though the page still has room for improvement: fjowners.wikidot.com/petcock

By the way: what would threading a brass nipple onto your petcock help with?

[fj11.5]

I think he,s saying its leaking at the outlet joint,  where the arm pushes into the petcock body

[Dan Filetti]

I think he,s saying its leaking at the outlet joint,  where the arm pushes into the petcock body

If so, put a twist-tie on it!  It can and will come loose, and spray gas on your hot motor.  This then will burn your FJ (and perhaps the house over it) to the ground, I know this from experience -not the house bit...  My advice: DO THIS NOW, WITHOUT DELAY -BEFORE YOU RIDE AGAIN.

Dan 

[fj11.5]

Dan knows the effect all to well if that fitting fails  ,, fix it from leaking, then as dan said tie it,jb weld it,  silastic it if you have to,  just don't leave it to fall out

[fintip]

I just thoroughly revised the petcock page, so it is a rather complete source of information (including the aforementioned safety subjects). Feel free to check it out. 

[mr blackstock]

I had the same problem with my FJ1100 '85.  Best solution I found was to coat the elbow in petrol resistant sealant, easy to buy from a local auto store, and wired up the elbow to the petcock with wire.

Been a few years and not a single drop has leaked out.

cheers, Gareth

[RichBaker]

I'd use some penetrating (green) Loctite 290..... It will penetrate and seal.  I've used it in oil environments and it works well. Don't see anything about gas, but I bet it isn't affected.

Assuming it IS the tube, and not the o-ring.

[eeshed]

Thank you all. Based on the great feedback I will do ASAP the follow : seal the tube with the locktite and wire. If problem is solved that's great. Second option, contact RPM and buy a unit. Third, in Woodstock Ontario a cycle wrecker just got FJ1100 for parts. I may get the petcok from the wrecker and explore a rebuild.
Eyal

[Tiger]

.... in Woodstock Ontario

Hi and welcome...where abouts in Ontariario are you?? I'm actually meeting with a new FJ'er, from Sarnia, in Woodstock tomorrow (Sunday) for a coffe at Timmies (10 a.m.) if you care to join us

BTW, I'm from Erin Ontario...

John.

[eeshed]

Hi John,
I'm in Burlington, may be in WS later this afternoon. Please send me your contact info to eyal@eshed.ca. We can try to work something out.

I am baffled by the fuel shut off. I disassembled it yesterday to clean and rebuild the leaky elbow pipe. I bored a 1/4 pipe thread and replaced the elbow with a 3/8 Barb 1/4 PIT brass Male Threaded Adapter. Got it at Home Depot for under $5 off the shelf. The Tapper thread I had to get from Low's. This fixed the fuel leak from the compression pipe. ! However, the fuel will not flow when the valve is on On position.

There are two positions for the valve; "On" and "Pri". When I put the valve on "On" the fuel doesn't flow at all, even when the engine is running and the vacuum hose is attached. When I put the valve on "Pri" the fuel flows freely even when engine is off.

I don't have the owner's manual and I don't know how the petcock should function. What should be the proper operation of the valve? When to use "Pri" and when to use "On"? What may be not working? Can I rebuild the petcock to function properly? 

Thanks,

Eyal

[FJmonkey]

There are two positions for the valve; "On" and "Pri". When I put the valve on "On" the fuel doesn't flow at all, even when the engine is running and the vacuum hose is attached. When I put the valve on "Pri" the fuel flows freely even when engine is off.

Thanks,

Eyal

Eyal, when the valve is set to "ON" it requires vacuum, not a lot but some for fuel to flow. A nice safety feature to stop fuel from flowing when the engine is off. It can be duplicated and or tested by sucking on it. With all but the vacuum line connected, suck on it. A good valve will act like a straw that is plugged and not allow any air in. A leaking valve will allow you keep sucking to maintain vacuum. If air is leaking then you will have fuel delivery issues. It took me a while to figure this out on my 27 year old petcock. So suck on your petcock and tell us what you think..... 

[eeshed]

Thanks. I will test for vacuum. Can I still ride with the petcock set to Pri?

Eyal

[fintip]

So suck on your petcock and tell us what you think..... 

I see what you did there...

Eyal:

You can, but it's a risk--the only thing stopping your tank from gushing out gas onto your engine when the bike is stopped will be the needles and seats in the carbs, and those aren't really the most reliable at performing that job (they are made to have a petcock doing most of that work, it seems). Ideally you should turn it off of prime every time you stop the bike, but it's a pain to access, so... That's lame.

You can install an in-line manual on/off switch. Or an inline vacuum switch, essentially replicating the original function of the petcock.

It will be easy to overflow the carbs if left on prime, however, and you also risk a fire (though the risk of fire in this particular case isn't as great as from the press-fitted piece).

tl;dr: Yes, you can, but it's risky. Be careful. Would be best if you turned it off of prime when stopped, sadly that's a pain.