Carburetor Tees

[Sparky84]

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

[FJ1100mjk]

I always replaced those o-rings. They get quite dilapitaded with age. I always separated the rack when refurbishing the carbs too.

[Pat Conlon]

Replace *all* O rings, especially the fuel T's and the float needle seats.

Buy this kit:





The best $22 you will ever spend: http://rpmracingca.com/proddetail.asp?prod=carbkit

[ZOA NOM]

Replace them.

[FJ1100mjk]

[Sparky84]

They get quite dilapitaded with age.

You were absolutely spot on and quite easily replaced. 
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 

Cheers Alan

[oldktmdude]

   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!
Bring it on, Pete.

[Sparky84]

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.   
Should I remove and refit hoses? That hasn't been done for years.
Or change  to clamps?

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 

Cheers Alan

[racerrad8]

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

[Sparky84]

Nice tip Robert, I will bench sync next then with gauges when running.

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

[racerrad8]

Out of sync. Check the fuel "Y" carefully for cracks. They are plastic and get brittle from heat and age.

Robert - RPM

[Pat Conlon]

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...

[racerrad8]

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

[FJ_Hooligan]

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.

[Sparky84]

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?

Cheers Alan