Carb is *@%^$*@%^$*@%^$*@%^$ing gas like a cow

[maisf]

Hi there,

Well, I just fixup my ignition problem and something else is failing...


I was trying out the bike and the ignition timing, all was fine, I even did my first gas tank fillup.
By the time I went back home, around 20 km later, I noticed a puddle of gas under the bike while opening the garage door.
Uh-uh... not good...
It looks like I did spread half of my gas tank around town... Lucky me it didn't drop on the exhaust or on the rear tire...
:concern:

So... my carb on the third cylinder is the one urinating all around (by the overflow of the bowl, from under the float bowl to be clear).
Some more facts:
- I did a "cleaned up" of the carbs when I got the bike. No it wasn't overnight dipped in cleaner, nor it was completly dissmembered. But I did disassembled the bottom section, floats needles etc..
- My petcock is mess up. I tried repairing a leak and ended up likely gluing the diaphragm closed. So I'm running the bike on the Primer position as it's the only way to get gas running out of the poor thing. A replacement is in order at the stealer for the petcock.
- As far as I know, carb adjustements is good. I have a nice idling, plenty of power on higher RPM, bike doesn't struggle on opening throttle, etc...

So I've narrowed my problem to the float system, either the float needle doesn't seal properly, or the float get stock in the down position.

Maybe the problem is running the bike on the primer side of the petcock? I mean, does the vacuum diaphragm would help in restraining the gas flowing in?

So before I unmount the carbs, should I order some new float needle and seat? new floats?
These needles weren't looking too bad when I cleaned them out 2 weeks ago...

Any advice?

Thanks guys!

Frank

 

[maisf]

Well, looks like I shouldn't say %$?ssing...

Is there a way to change the title of this post?

lol

 

[Nessism]

Please check the Newbie Mistakes thread link in my signature. It will help you.

 

[Brendan W]

Can't let these things sit on prime, it's asking for trouble. Sort the petcock and the success rate with rebuild kits is low.
Was it on the centre stand or sidestand? Occasionally mine will leak on prime on sidestand.
Check your oil level and smell it for gas, although everything probably smells of gas right now.
Don't run it with gas in there.
Don't order anything until you have a look at the floats and needles.

 

[maisf]

Please check the Newbie Mistakes thread link in my signature. It will help you.

Well thanks a lot, I think I've read it all.

 

[maisf]

I know, I'm not letting it stand on prime, it's just to have the bike running. I'm shuting off the petcock as soon as I shut the motor.

No gas in the motor, oil level is fine.

The leak is while it was on either stand... makes no diff.

 

[Big T]

Please, don't tell us what model bike or carbs you have
Wild speculation is for Facebook

Put your year and model in your signature, so we're not completely clueless

 

[sam000lee]

A fairly common source of leaks to look out for are the "fuel rail" pieces that go between the carbs. Between 2&3 is the fuel "T" and between 1&2 and 3&4 are straight connectors with O-rings. Any of these linkages can leak, especially if the O-Rings between 1&2 and 3&4 are original. They come with the O-Ring kits recommended to rebuild GS carbs at cycleorings.com.

 

[maisf]

Please, don't tell us what model bike or carbs you have
Wild speculation is for Facebook

Put your year and model in your signature, so we're not completely clueless

Oupsie sorry!

GS850 1979 --> carbs are VM

I'm fixing this signature right now...

 

[maisf]

A fairly common source of leaks to look out for are the "fuel rail" pieces that go between the carbs.

Well, I did put see through plastic lines on the bowl overflow and I can see it's leaking through these. I guess a fuel rail leak wouldn't leak from inside the bowl but would spilled over directly on the crankcase... right?

 

[Guest]

Well, I did put see through plastic lines on the bowl overflow and I can see it's leaking through these. I guess a fuel rail leak wouldn't leak from inside the bowl but would spilled over directly on the crankcase... right?

Try tapping the float bowls with the handle of a screwdriver. Sometimes the floats can get stuck and cause an overflow.

 

[Brendan W]

You could also try opening the drain screw and let the fuel run through at full chat for a few seconds. With the floats fully down a big piece of grit has a better chance to clear the float needle. Which carb(s) is it?

 

[maisf]

Which carb(s) is it?

I guess it's the third one as it's feeding the cylinder #3...

80GS1000 : I'll try this! The more I think about it the more it make sense that the float is getting stock down low. A needle problem would be more likely a slow leak I guess... Unless some grit got stock like Brendan suggested...

Both are good ideas! I'm trying them now!

Thanks guys!

 

[maisf]

Well, tapping the bowl didn't show any improvements.

But..... Opening the drain screw on the offending carb did make the problem disapear!

At least for a few kms. The leak got back as worse as ever and I made a donation of 4 or 5 liters of gas to the speed gods getting back home.

I guess I'll be tearing this apart this weekend.

 

[maisf]

I called my local Suzuki dealer yesterday, saying to myself, what the heck just change all these float needles and all will be good...

Gulp... That's 254 CAN$. It's quite a bit steeper than I thought...

I read someone talking about getting those from Amazon at 15 bucks a piece but I couldn't find them as of now.

From your experiences, would it make any sense to just replace the faulty one?

 

[Brendan W]

If the needle is the problem I would expect to see some sign of wear on the tip significantly different to the others.
Back to basics, mechanical float level, fluid float level, float sticking.
In the days of hollow floats there was even float sinking to check out.
With a bit of luck opening cleaning and rebuilding cures mystery faults.
Keep your wallet in your pocket until you find a smoking gun.
Even then I'd take my chances with a used carb for oem parts rather than anything cheap on the internet.

 

[maisf]

Of course, I wasn't talking about some third party replacements, I'm looking for OEM...
A used carb seems like a far fetch, pre 1980 bikes seems sparce around here.

Anyway, I don't mind spending some cash, as long as it's not too much, and as long as it fix the /%$/%/ problem...


So they have them (float needels and seat) at Z1 for 20 US$ but then it's the shipping to Canada that's killing me.

I think you're right, I'll have to unmount this again first and have a through look at all this. I don't remember the float needles being that bad... But then, maybe the previous owner changed them without changing the seats!

The float height specs measurement method is still unclear to me. It's measured with the carb upside down, from the very top of the float to the gasket surface, with needle depressed or not?

And for measuring fluid level, I need a clear tube with some sort of an adapter in place instead of the bowl drain plug, right? I've seen this setup for sale at Z1, with same shipping issue as for the needles... gosh...

Hehehe no easy way out!

 

[Guest]

I had the same problem (never run on reserve if your gas tank is full of rust). I just took the carb out, bounced the bouncy bit and the float a bit and put it back on. Worked like new afterwards.

 

[Big T]

The float height specs measurement method is still unclear to me. It's measured with the carb upside down, from the very top of the float to the gasket surface, with needle depressed or not?

And for measuring fluid level, I need a clear tube with some sort of an adapter in place instead of the bowl drain plug, right? I've seen this setup for sale at Z1, with same shipping issue as for the needles... gosh...

Hehehe no easy way out!

You've never read Nessism's carb build tutorial?
Where are you getting your information?

 

[chris]

Or you can kick the 40 year old carbs to the curb, and get a set of Mikuni rs34. More midrange power and no PIA airbox required. Lots of pluses except cost.