Just installed new jets, needle and seat inside carbs after ultrasonic clean, now just filled them with fuel to check for leaks before installing back on bike.
I didn't seperate the rack (not that confident) , I did notice when pushing on the "Tees" between the carbs where the fuel goes into bowl that fuel leaked but when sitting there none.
Is that normal with the Tee pieces that when you push or twist that they leak or do I need to replace the o-rings?
Cheers Alan
I always replaced those o-rings. They get quite dilapitaded with age. I always separated the rack when refurbishing the carbs too.
Replace *all* O rings, especially the fuel T's and the float needle seats.
Buy this kit:
(http://rpmracingca.com/prodimages/large/carbkit-1.jpg)
(http://rpmracingca.com/prodimages/large/carbkit-2.jpg)
The best $22 you will ever spend: http://rpmracingca.com/proddetail.asp?prod=carbkit (http://rpmracingca.com/proddetail.asp?prod=carbkit)
Replace them.
(https://i.imgur.com/q96WRy0.png)
Quote from: ZOA NOM on November 07, 2017, 11:42:07 AM
(https://i.imgur.com/q96WRy0.png)
(http://fjowners.com/gallery/10/1388_07_11_17_11_48_02.jpeg)
Quote from: FJ1100mjk on November 07, 2017, 09:44:07 AM
They get quite dilapitaded with age.
You were absolutely spot on and quite easily replaced. :drinks:
Just had to separate the outside ones.
3 screws on choke bar which even had indents on bar to locate them.
Remove the throttle sync springs (don't even need to touch screws)
And the 4 rack bar screws and the outside ones can be removed so you can replace the o-rings.
I can push wriggle twist those tees and no leaks :biggrin:
Cheers Alan
Good job Alan. You can't take a risk with possible fuel leaks as shown above in graphic detail.
The only problem that I see is that you'll have nothing to fix next month and we'll have to buy more beer! :drinks:
Bring it on, Pete.
Just noticed fuel leaking on the "Y" piece on top of the carbs while I was leak testing, it didn't leak from there yesterday. :dash2:
Should I remove and refit hoses? That hasn't been done for years.
Or change to clamps?
Quote from: oldktmdude on November 08, 2017, 03:54:53 AM
The only problem that I see is that you'll have nothing to fix next month
Bring it on, Pete.
Don't Worry Pete, I haven't fitted the Shift Detent Kit yet and I thought while we're in there I got a Barnett Spring Plate to fit also, just for you Mate :drinks:
Cheers Alan
You are going to want to re-sync the carbs even though you didn't turn the screws(if you have already synched them). We have found they are usually never the same after removing the springs and dis-assembling for cleaning; even though we do not mess with the adjustment prior to cleaning. And we also have the same problem when dis-assembling brand new carburetors to convert over to gravity feed for customers as well.
Robert - RPM
Nice tip Robert, I will bench sync next then with gauges when running.
Quote from: racerrad8 on November 08, 2017, 10:15:38 AM
And we also have the same problem when dis-assembling brand new carburetors to convert over to gravity feed for customers as well.
Do you mean out of sync or fuel leaking at the "Y" piece Robert?
Cheers Alan
Out of sync. Check the fuel "Y" carefully for cracks. They are plastic and get brittle from heat and age.
Robert - RPM
Let me expound: All the new sets of Mikuni BS36 carbs are set up with a center fuel T used on the fuel pump models.
When converting these carbs over to gravity flow for the '84-87 customers, RPM installs the fuel T's between carbs 1/2 and 3/4 along with changing the float needle seats, just like oem.
The single center T used on the fuel pump systems does not play nice with the reduced fuel pressure used on the gravity flow systems.
Anytime you pull the carbs apart...synchronize them.
If you're leaking from the fuel line Y fitting, figure it out quickly and fix it. No carb sync is needed to work on the fuel line....just when you pull the carbs apart.
Sync'ing the carbs is easy....I check my carbs once every year or two...
Yes, Pat is correct.
I was referring to the pulling of the springs when he replaced the leaking o-rings in my original reply. Should have explained better originally.
Robert - RPM
About 6 years ago, the original carbs on my '85 FJ started seeping fuel. I replaced the needle seat o-rings, swapped needles and seats from a different set of carbs and even installed new floats. Nothing would stop the slow seeping. It was not a gusher. With the carbs held upright in a vise, I would hook up an external tank. It would take a few hours, but eventually fuel would begin dripping out of one or more of the 4 choke circuit air intake hoses.
I jacked with it for several weeks before finally giving up and switching to a set of pump carbs that I bought from Bob W. I didn't bother to change the needle seats over to the old gravity feed units because I thought they might be a contributor to the seepage problem I was experiencing.
The only thing I changed on the carb rack was to split them apart between carb 2 and 3 and install one of the gravity feed inlet Tees. I did this so the feed hose from the tank would be 10mm ID instead of 8mm. The gravity T was shorter than the pump T so I spaced it on either side with a tie-wrap to keep it from sliding back and forth. Both o-rings engaged on each side so there were no leaks.
Going to the single gravity feed in the center gave me enough room to use a Colder SS Double Shutoff Quick Disconnect fitting on the fuel line. This keeps me from having to pull the line off of the petcock and putting stress on the petcock fitting.
I haven't pulled these carbs in the 6 years since they were installed. I've pulled the tank a few times, which is a breeze with the Colder fitting.
Concerned about fuel delivery, I performed several experiments. I've run the tank low enough until the fuel light was glowing brightly while running at high(ish) speed down the highway. I've run the tank low while running aggressively on twisty roads. I have experienced NO problems with fuel delivery or starvation. I've also discovered that the groups I usually ride with have nowhere near the mileage range of the FJ so we typically stop for fuel well before the tank is anywhere near empty.
As usual; YMMV, wear your gear all the time, don't drink and drive, and most importantly, keep out of reach of small children and software engineers.
Y piece looks good but lines look moulded to the Y and maybe slight movement may have moved them from original position that they have been sitting in for awhile.
If I replaced Y with another it might seat on fuel line in different place and seal better? :scratch_one-s_head:
Cheers Alan
So they Y piece is good, no cracks, I cleaned tubes and held ends in boiling water hoping the ends may revert back to their normal size :scratch_one-s_head:, no leaks now.
Back to leak test and found no more leaks :good: but there is fuel in the Main Air Jet :scratch_one-s_head:
Is this normal as I wouldn't think it was and on the drawing it states Air goes in, unless when it sits a capillary action occurs and fuel does go up that small pathway?
Getting closer I hope to fitting them back on.
I don't understand why you didn't replace those hardened fuel lines? I guess it is your risk.... Hardened rubber cracks easily and there are some constant vibrations, not to mention the heat.
Quote from: balky1 on November 10, 2017, 07:05:07 AM
I don't understand why you didn't replace those hardened fuel lines? I guess it is your risk....
That's not the problem at present....... lines seem good. If I could buy the replacement of what I have maybe I would but I cannot...... (I would definitely like a quick connector and longer fuel line to make removal of tank a lot easier.)
The main problem was o-rings as depicted above and now I need to know if there should be fuel visible in the Main Air Jet at or not after it sits there doing nothing which has nothing to do with the fuel lines
Cheers Alan
If your lines start leaking at connections just because of a small wiggle than that rubber is shit. Just remember what you found on the Ts that leaked after wiggling.... A meter of fuel line costs les than 2 USD in Croatia (a meter and a half is more than enough to change it twice) so I don't think it is any more expensive over there? I mean, to risk the fuel leaks for such money? Your call I guess. But in the end, you are the one that will be removing all that once again, probably soon, to replace the lines. Half measures get you nowhere. This is just a good will advice, don't get me wrong.
On the longer lines... Hmmm, I wander if that will work on an '84? There's no space under the tank when you lower it in place to acommodate more line without pinching or kinking I think.
Quote from: Sparky84 on November 10, 2017, 05:15:28 AM
but there is fuel in the Main Air Jet :scratch_one-s_head:
Is this normal as I wouldn't think it was and on the drawing it states Air goes in, unless when it sits a capillary action occurs and fuel does go up that small pathway?
Due to valve overlap, there is a fuel mist that normally comes out of your carbs (on the inlet side)....the same fuel mist that play's havoc with K&N filter pods by washing away the filter oil on the cotton.
From this fuel mist, you may notice a residue of fuel on the air jet orifices, nothing to worry about.
If you're dripping fuel out of the air jets....then yes, you've got a problem.
Please be safe with your fuel lines... :bomb:
Quote from: Pat Conlon on November 11, 2017, 10:37:40 AM
From this fuel mist, you may notice a residue of fuel on the air jet orifices, nothing to worry about.
If you're dripping fuel out of the air jets....then yes, you've got a problem.
Not Dripping but it has fuel in orifice of the Main Air Jet (the one you cannot remove) so you can see it
but this is while the carbs have been on a bench sitting while leak testing will the same apply?
Quote from: Pat Conlon on November 11, 2017, 10:37:40 AM
Please be safe with your fuel lines... :bomb:
This is why I'm checking before installing, Just playing it safe
Quote from: balky1 on November 11, 2017, 03:58:25 AM
If your lines start leaking at connections just because of a small wiggle than that rubber is shit.
It was leaking out of O-Rings on the Tee between the Carbs not from the lines on the Tee.
Quote from: balky1 on November 11, 2017, 03:58:25 AM
without pinching or kinking I think
I thought you could not replace the fuel lines due to this problem with the routing causing pinching and kinking due to the fact they have been formed and hardened to fit?
Cheers Alan
Bench test them: While you have your carbs out, orient them to the running position, now hook up an external gravity fuel tank, fill the float bowls, then let the carbs sit for awhile...see if you have any drips.
You should not have any drips.
Pat,
That's how I leak tested with a 300ml container overhead, no drips but fuel in the jet, all 4.
I'll blow the jet clean with air and set them up again.
It was set up for 2 days before I noticed this happening.
I'll also check fuel level in the bowls after this time (which I forgot to do when I noticed this)
Cheer Alan
You can put any fuel rated hose that is heat resistant. Routing is important to prevent kinking. You should have the routing diagram on the air-box if it's still there.
Quote from: Sparky84 on November 10, 2017, 05:15:28 AM
Back to leak test and found no more leaks :good: but there is fuel in the Main Air Jet :scratch_one-s_head:
Ok, so I found this on XS11 carb FAQ site which confirms what I'm seeing, fuel in the Main Air Jet seems to be normal.
Q: What does the main air jet do and what effect does changing to a larger or smaller size have?
A: This jet is pressed in and cannot be easily replaced. It does tend to get gummed up and must be cleaned very well. This jet bleeds air into the needle jet to emusify the fuel and dilute it for more precise metering by the jet needle. Larger air jet gives a leaner mixture and smaller (or plugged up) jet gives richer mixture. http://sense.net//~blaine/xs11carb.html
So this tells me fuel is present in the Main Air Jet quite a bit of the time if it's getting "gummed up".
:rofl2:
Cheers Alan
Fuel reservoir is higher, at present its got about 100ml in it via a 6mm to the 5/16" pipe to carbs.
Carbs are level in vice, both ways.
Floats have been checked and set to height recommended.
Fuel level has been checked using clear graduated tube.
At present 4mm below carb body as indicated by blue line, 3mm +/-1mm is in the GYSM.
Pictures and measurements are taken after 2 days on the bench.
Fuel is still present in Main Air Jet, I can even siphon fuel from it with a syringe! :bad: or :good:
I'm still unsure if this is correct but all measurements seem to be correct
Cheers Alan
You are actually 5 mm below the carb body. Clear fluid level is measured at the bottom of the meniskus. https://www.thoughtco.com/how-to-read-a-meniscus-606055 (https://www.thoughtco.com/how-to-read-a-meniscus-606055)
Quote from: balky1 on November 15, 2017, 05:29:47 AM
You are actually 5 mm below the carb body. Clear fluid level is measured at the bottom of the meniskus. https://www.thoughtco.com/how-to-read-a-meniscus-606055 (https://www.thoughtco.com/how-to-read-a-meniscus-606055)
Quote from: Sparky84 on November 15, 2017, 02:07:05 AM
Fuel reservoir is higher, at present its got about 100ml in it via a 6mm to the 5/16" pipe to carbs.
Carbs are level in vice, both ways.
Floats have been checked and set to height recommended.
Fuel level has been checked using clear graduated tube.
At present 5mm below carb body as indicated by blue line, 3mm +/-1mm is in the GYSM.
Pictures and measurements are taken after 2 days on the bench.
Fuel is still present in Main Air Jet, I can even siphon fuel from it with a syringe! :bad: or :good:
I'm still unsure if this is correct but all measurements seem to be correct
Cheers Alan
I have Fixed It :dash2:
Thanks Balky1, you are a Guiness, you should have been a Virtual Mechanic.
Cheers Alan
I was easily able to drain the level in the fuel bowls using a syringe to pretty close to the level of the bottom of the Main Jet.
I'm glad if I helped.
I don't think you should worry about that fuel unless it siphons out by itself.
Furthermore, did you disconnect the fuel reservoir when you were pulling the fuel with a syringe? Because if you didn't and there is fuel in the tank, the float bowl shouldn't get emptied.