FJ leakin fuel

[magge52]

I can see 3 tubes under there but the dripping has stopped so I'll quit for now and regroup.

[magge52]

Tried tapping the carbs again tonite but the same leak is there from the rt side carbs. So it looks like its time to dig deeper. I'm siphoning the tank, any surprises to look out for taking it off?

[magge52]

Removed the tank and with better access to the carbs I tried the light taps again. Put some gas back in the tank and started her up...same old song. A steady stream shortly after starting slowing to a drip after shutdown and the drip stops after a couple minutes. Does this sound like internals that are worn/stuck or something outside the carbs? I'm at the point of removing the oem air cleaner so I can stop here if it's external. I can only see 3 drain tubes but apparently there are 4 or 5 in there, don't know if this is a factor. 12k miles on a stock setup, no known maintenance history for the carbs.

[FJ1100mjk]

George:

Sounds like you'll need to pull the carbs, remove the float bowls, and see what's going on with them. Even with only 12,000 miles on the bike, having no history on the upkeep of the carbs puts you in this position. At least that's how I'm seeing it.

The float(s) could be stuck or dragging on their pins, because their gummed-up with old fuel varnish. The float needles could be doing it too. Float level(s) might be off. You don't know, what you don't know.

A good cleaning and inspection is in order. At least buy the RPM Racing o-ring and stainless steel screw kit before you dig into them.

If you're not up to doing it, consider sending them off to RPM Racing for a quick turnaround.

Good luck!

[ELIMINATOR]

I seem to have cured my No. 3 carb. from leaking, by blowing down the overflow pipe. Did this without the engine running. Then with the engine running.  Cheapest option to try first

[magge52]

George:

Sounds like you'll need to pull the carbs, remove the float bowls, and see what's going on with them. Even with only 12,000 miles on the bike, having no history on the upkeep of the carbs puts you in this position. At least that's how I'm seeing it.

The float(s) could be stuck or dragging on their pins, because their gummed-up with old fuel varnish. The float needles could be doing it too. Float level(s) might be off. You don't know, what you don't know.

A good cleaning and inspection is in order. At least buy the RPM Racing o-ring and stainless steel screw kit before you dig into them.

If you're not up to doing it, consider sending them off to RPM Racing for a quick turnaround.

Good luck!

Depending on the cost I may go with RPM for the plug,n,play convenience but owning a Norton for 27+ years you gotta know your way around a toolbox.

Eliminator-like your idea, may give it a shot but a more permanent fix is probable. Luckily the leaks started Sunday morning warming it up in my driveway. Would have been a tough situation happening a couple hundred miles from home...

Thanks for the input gents.

[JOMPPA10]

HI
i fixed carbs with carb repair kits and tested and tested them by connecting fuelpump to hole carb package, finaly they didnt leak from over leaking hoses
Then i put them back and bike was running fine and i go to test drive everything vorked fine abouth 5 miles and then bike was startig run rough and woudnt
keep idle. i crumble back to my home and pull off carb package, they vere owerflovig to cylinders, please any anver to that? , and my bike is still 3cv.
BIG but my tank has only one out line with some white tap which can used by wrench to cut off fuel supply , nothing else just direct line to filter then pump.
is this correct? Has prewious ovners don some modification to fuel system, carbs have one input not two and fuel lines are pretty thin 6mm i belive. i have
also electric reserve switch in panel next to choke.

[simi_ed]

That all sounds identical to my '89 (3CV).  When you bench tested the carbs, did you angle them, as they do not mount EXACTLY horizontal? 

I would suspect your float level is not correct.  I would take them off to verify float level is midrange per the service manual (Per GYSM, spec is 21.3 - 23.3 mm or 0.84 - 0.92")
Please report back.


Ed

[andyb]

If the float height is right, you can snap to WOT from a 2krpm cruise and it'll pull cleanly (albeit not very well, but no spluttering).  Leaking is a lack of sealing, and that's a problem, not a misadjustment of the height.

[JOMPPA10]

PROBLEM SOLVED

One of new needleset needles wanted to stuck in needle frame, needle was little pressed down and aluminium in frame had little bulk. I smoothen lover part of needle and then it worked fine
Next i set fuel levels much lover tha than originals (needle was right but needleseat was deeper, so levels vere way too up).
So what i learned: dont buy cheap needle/repair set!, you got lot of work with them! . But thanks to you all with helping me.

[aussiefj]

I've had exactly the same problem on my '93, checked everything but would still reoccur from time to time, managed to break one of the posts trying to get the float pin out, repaired it with araldite out of desperation and it held for around 12 months without a problem, but the flooding still occurred on and off. Finally I bit the bullet and bought a new set of carbies off Randy, not long after it happened again, that was about 12 months ago and it hasn't happened since but I wonder if it's something other than a fault in the carbs. Could it be the fuel pump over- pressurizing, does it happen to earlier models without fuel pumps? Is the fuel pump really necessary, will the later models run on gravity feed?

Cheers, John.

[ribbert]

I've had exactly the same problem on my '93, checked everything but would still reoccur from time to time, managed to break one of the posts trying to get the float pin out, repaired it with araldite out of desperation and it held for around 12 months without a problem, but the flooding still occurred on and off. Finally I bit the bullet and bought a new set of carbies off Randy, not long after it happened again, that was about 12 months ago and it hasn't happened since but I wonder if it's something other than a fault in the carbs. Could it be the fuel pump over- pressurizing, does it happen to earlier models without fuel pumps? Is the fuel pump really necessary, will the later models run on gravity feed?

Cheers, John.

Firstly, fuel pumps are better (but that's another story) The gravity feed models have trouble just trying to get fuel into the carbs.   

The forum is never more than a few days away from someone raising this problem. Some blokes rip their carbies off every time this happens and clean them. I just accept that they have bouts of incontinence. Mine has only done this for the last 100,000kms. Sometimes it will do it three or four times in the one day, sometimes it will go for 20,000kms without happening.

Many different views are held on what causes it and how best to deal with it but it is very common. I either tap the bowl of the offending carby with a metal rod (that I carry at all times for just this purpose) and/or you can empty the bowls in place with the drain screw, they are easily accessible and only takes a few seconds. Back off the screw, let the fuel run out, tighten it up again.

While it is annoying when it happens, I know it comes and goes and don't think too much about it, just fix it and keep riding. One thing I have noticed is that it seems to happen more often when I have been creeping around at very low revs, like heavy traffic. I have also noticed that a big rev sometimes clears it.

Don't be disappointed in your new carbies, they all seem to do it regardless of age of mileage.

Noel

[aussiefj]

Bouts of incontinence, I've never thought of it like that, but I'm fast approaching that age so I guess I can accept that. I usually use the big rev to clear it, but I worry about raw fuel running into the inlet ports and contaminating the oil, does this happen?

John

[Fj.itis]

Polish the insides of the seats up with a q-tip in a drill and some brasso or polish, brings them up smooth and better then new. Its definately the needles sticking open on most cases as the walls of the seats get a bit sticky.

One thing to look out for is flat spots on the side of the seats, previous owners or yourself may well have squeezed a little hard when trying to remove and causes them to go out of round.

[sbikebee]

I have just started a thread about a fuel pump that allows fuel by when shut off. It definitely was a leak after about 4 hours of sitting. The weight of the fuel above the carbs unrestricted can over power the floats.