Still Leaking

[Lloydo]

Help!!! I posted a while back about gas leaking into the air box. It was suggested that there was a piece of dirt, or something, clogging the float seat/needles. I pulled the carbs, replaced the float seats & pins, replaced the main jets, adjusted the float height, & rebuilt the fuel petcocks. ( As fuel was also continuously flowing from the tank, no matter what petcock setting I tried. ) I got the bike running again yesterday, a little so-so at first, but after raising the idle to around 1000, & fiddling a bit with the mixture screws, didn't seem too bad. I opened the garage this morning, planning to sync the carbs today, only to find a large puddle of gas under the bike, with a steady dripping coming from the drain hole on the airbox! 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. Any thoughts on what I may have missed? As many of you know, pulling the carbs is no picnic, I'd really hate to go through all that again. I want to ride!!! It's a '79 Special SF. Thanks for any help.

[renegade_xs11g]

I Hate to be the bearer of bad news...

But I think you're gonna have to pull them carbs again.

just a thought... you've probably got a float hanging up on the bowl.

At least that's what mine was.

Sorry, and good luck
John

[renegade_xs11g]

Just another thought...

if you can disconnect the air box...
turn on the fuel...
watch the fuel come out of the airbox side of the carbs...
at least you'll be able to tell which one...

again good luck

[gwh57]

Hi I had this problem with a 82 seca 750 it turned out to be a faulty gas cap. The cap would not release the pressure from the tank and forced fuel pass the needles. Try leaving the cap opened a little.

[rman]

Re: Still Leaking

Originally posted by Lloydo
I thought fuel wasn't supposed to flow with "on" or "res"? Although set to "off" at least works, gas doesn't flow. Any thoughts on what I may have missed?.

Your petcocks have an "off"? Should have "On", "res" and "Prim"
On, reserve and prime.???
Are these stock vacume type?

Disclaimer: I am an idiot. Pay no attention to the man behind the curtain.

[gwh57]

Hi, Yes the 82 seca 750 has "on", "pri", "res" and are vac operated. This is the same setup as my 82 xj1100. The pressure will force fuel through the petcock and needle valves in carbs. This happens when sitting not running.

[Wildkat]

Re: Re: Still Leaking

Originally posted by rman
Your petcocks have an "off"?

Off, on, res AND prime on the Specials... see how special they are?


We turn ours off every time we park them as they do tend to piddle... but if yours is a puddle... then there is a problem...

Past experience in the puddle area, for me, has been a stuck float...

[mro]

When you get puddles

Fuel has to get past both the petcocks and float needles.
Can just disconect fuel line from petcocks to see if they are leaking.

Debris/rust in fuel tank???

Takes only a tiny bit to stick open a float needle.
In-line fuel filters may help if this is the case.


mro

[underdog57]

My floats gave me a run for the money adjusting them .
Not sure if it helped , but I put them at 26MM and turned them right side up and rotated them a few times . Thought was to be sure they are riding on the tang and settled in ...
There is supposed to be little screen under the float needle seat .
they show available but just under 9.00 bucks each from yamaha.
wonder if there is a cheraper source??

Good luck
, I chucked my octopus and run on prime with an inline shutoff plus filter .....

Bob

[Lloydo]

Thanks for responding so fast..........
When I but the new float pin seats in, I did pull the old screens off the old float pin seats, & snapped them on the new ones. One difference I did notice, if it matters, is that the old seats had a reddish fiber sort of gasket, the new ones had just a metal washer?
I did hook up the fuel lines with the airbox removed, nothing. So now I'm taking a break after the fun task of pulling the carbs again. I did notice while twisting & turning them to come out, that fuel was coming out of #4. After I got them out & tilted the carbs towards me, that fuel comes out of the little hole on the bottom right, ( Facing the back of the carbs. ) & from the throat itself as I tilted them more. I'm guessing that if you tilt the carbs far enough, the floats will "open" & fuel will come out. But #4 seemed to leak the most, a little came out of #1. Could 4 be the culprit? As far as the gas cap.......... I kind of remember hearing a little "hiss", when I opened it to refill, so it seemed to always have a little pressure in it. I never had this problem with gas filling the air box, and it seems the crankcase too, as the oil indicator shows it as overfilled, when I had it running yesterday & shut off, the oil level was halfway up the window. Of course 4 qts of new oil shot again! Hopefully someone has an idea!

[wingnut]

Take them off agian remove the float seats. Clean eveything and use compressed air on the passages. Check the floats for internial leaks/holes. Put them back togerher and adjust/check the float level. Once you are sure the levles are where you want them set the carb bank in a level position and apply a fuel source to both sets. If you have a leak this is where it will show up. Better than after you put them back on the bike. What condition is the inside of the tank? If rusty you may need to go the KREEM route. Inline filters are also a good thing. I'm no GURU but I just went thru the same thing on a set of carbs on the 650.

[Snow]

Forgive me if this was already stated, but I didn't see it... how easily did the float pins come out? Did you verify they were straight and had no pitting/corrosion?

On one set of problem carbs, I eventually replaced the pins with new ones pretty cheaply from bikebandit...turned out they were the last problem.

[Lloydo]

Thanks wingnut. The inside of the tank looks almost brand new, I was surprised when I pulled the filters out to do the petcocks, there were maybe 2 minute specks on the filters. Other than that the filters looked new. Will blowing air in any passage I can hurt anything else, as I only have the float bowls off, didn't want to completly dissassemble the carbs. One thing I did notice, I drained the bowls through a coffee filter into a gas can, & noticed a few specks of stuff when I drained #4, & a few more, maybe even a little bigger than those, when I drained #1. Do you mean to supply fuel with the carbs upside down, & the bowls off? Or to but the bowls on, set them upright & see if gas comes out through the carb, as it does on the bike.

[Lloydo]

By float pins, I assume you mean the pin that goes through the float, through one post, & then tightly into the other. ( Use a sidecutters to remove, I learned here) They seemed fine, once I loosened them with the sidecutters, they slid easily the rest of the way. They also look fine, clean & straight.

[underdog57]

Look in the tech tips , good stuffon cleaning carbs in there ...
You want to remove everything , do not dunk unless you pull butterflys...
Yank out the main jet then top covers to get the jet needle out .
you can get the needle jet (emulsion tube) out ...
Idle mix , remove it , carefull it breaks easy on the 78/79...
pull ot the air jet ...
pilot jets are under a screw near the mains , kinda delicate , but cheap in case you have a misshap .I used a left hand drill , but bet an easy out if worse case happens ...
Carb spray till you get cleaner coming out , then blow it out with comp. air ...every entrance should have a passage for the spray to exit , watch your eyes , yes I did squirt carb cleaner in my eye..
dont forget the orifice in the bowls , that is for enrichener ....clogs easy ...
Sounds like your carbs are not too dirty ..
Hope it comes clean for you

Bob