Still Leaking

[Lloydo]

Neat, this is almost like an on-line chat! I just checked the floats, no leaks there. I guess you're right, I've gone this far, it makes sense to dissassemble them all the way & do it right. The rebuild kit does have the long needle for the main jet, new mixture screws, etc. I just thought I could get cheat and get away with doing the "bottom end" of the carbs. Look where that got me!

[HobbyMan]

new ocy units are available from yamaha for about $50 I think. Maby a little more. You could just rebuild it(iffy) Polish the float seats with a Q-tip in a drill. Then do a pressure test. I set an old oil jar with a bunjee around it plumbed right into both inlets. If it does not leak out with pressure on it, your floats are fine.

[wingnut]

Bench Test

Here is how I bench test carbs;



I've got an 81 which has nipples on the bottoms of the fuel bowls. I use the clear tube method discribed in the manuals for checking float levels and it lets you test for leaks at the same time. A little messy and time consuming but it works for me.

[skids]

Re: Bench Test

When you do the U-tube manometer method, what on the carb body do you use for reference and what is the spec? I notriced that there is a difference between the side of the floatbowl flange and the back. Do you use the center of the maniscous or the edge of the fuel against the tubing?

Originally posted by wingnut
Here is how I bench test carbs;

A little messy and time consuming but it works for me.

[underdog57]

u-tube level

3 +or - 1mm (0.12 + or - 0.04") below the carb mixing chamber edge . this is where the bowl screw sits on ..
this is for 82 xj

Bob

[wingnut]

Yep that's it and with that kind of tolerance I don't worry to much on the edge of the fuel or the maniscous.

[Ljay40]

One thing I have not seen mentioned here that I had problems
on is make sure the rubber O ring on the seat is in real good shape gas can leak past that I took the seat to the local hardware store and found 4 new 0 rings for 25 cents a piece
cheap and easy fix.After setting my floats amillion times it was my
O rings
just a thought

[underdog57]

Originally posted by Ljay40
One thing I have not seen mentioned here that I had problems
on is make sure the rubber O ring on the seat is in real good shape gas can leak past that I took the seat to the local hardware store and found 4 new 0 rings for 25 cents a piece
cheap and easy fix.After setting my floats amillion times it was my
O rings
just a thought

The O-rings are on 80 -82 carbs for the 1100 , 78/79 screw in with a washer to seal ...

Bob

[Parr8hed]

A little added insurance is an in-line fuel shutoff. that is what I did after I went through the carbs on mine. put one on each side and can shut them off completely now.

[fredintoon]

Octopus?

Hi Lloydo,
you posted:-

"I pulled the tank, noticing that fuel still flows with the petcock turned to "on". I thought fuel wasn't supposed to flow with "on" or "res"? Although set to "off" at least works, gas doesn't flow."

If you pulled the tank but left the octopus valve on the bike YES the "on" and "res" fuel valve positions will flow gas. Remember that on a Special it's the vacuum operated octopus that turns a forgetful fellow's gas off for him. Of course, the "prime" position bypasses the octopus and will flow gas anytime. That said, turning the gas off don't fix the problem, it only hides it. Betcha one or more of your float needle & seat valves ain't working.
Fred Hill, S'toon.

[Lloydo]

Thanks again all. I have the carbs off again, any thoughts on removing the brackets, as the manual suggests, & separating the carbs for cleaning? Is there any thing that could be harmed by not doing so? Or is that more not to mix up parts. I have them torn all the way apart, the only thing I wonder about is the T connections between carbs, & the choke connection between them, if I dunk them, will any of that stuff be harmed. If I do dunk them, what have you all had good luck using for that? Thanks again.

[Ken Talbot]

- If you dunk them all together, you will ruin the seals on the butterfly shaft.

- You can get the choke assembly all apart without separating the carbs from the rails.

- With some canned carb cleaner spray, some careful work with fine wire, and compressed air, you should be able to get all of the passages clean with the carbs still attached to the rails.

[fredintoon]

Hi Ken,
I have dipped my carb bodies, admittedly for less than 4 hours and the butterfly shaft seals still seem OK ("gotten away with it" may be a more accurate statement) If you can do a proper cleansing with aerosol carb cleaner it's a safer deal.
BUT, can those big ol' enrichener plugs be threaded out with the carbs still bolted into their rails? Theres little holes behind those things that need a blowthrough.
Fred Hill, S'toon.

[Ken Talbot]

Oops - you are absolutely correct, fredintoon. It is impossible to remove the plunger of the enrichener mechanism without almost totally dis-assembling the carbs from the mounting rails. Without removing the plunger, you would not be getting that part of the carbs truly clean. I will try to remember that for next time a newbie is asking.

[fredintoon]

Annanotherthing - - -

Hi Ken,
while advising carb-cleaning newbies, some more pointers:-
Clean 'em one at a time. That way you still have 3 good ones to check that all the parts went back in the proper place.
The idle mixture needles have a spring, a washer and an o-ring on them. The spring mostly lifts out with the needle but the teensy washer & o-ring tend to stay at the bottom of the hole. Fish 'em out with a home-made hookything, bash a bent-over flat onto the end of a piece of 16ga welding wire and grind it short enough to fit down the hole & lift the washer & o-ring out before the blast from the carb cleaner spray washes them away to be lost forever.
Buy a rebuild kit & it comes with a rubber bung that plugs up the hole to the slow running jet. Install those on my '80 Special & some others and entirely block off the jet. Toss 'em or use them as dust seals for the idle mixture needles.
Fred Hill, S'toon.