Float valve?

[Hook#3287]

I was draining my carbs and two of them wouldn't, kept leaking gas. ??? ???

I had rebuilt my OEM petcock last feb, so I thought I was good there.  Obviously not.

Took tank off, pulled petcock apart, couldn't see why, but it was sticking.  Cleaned it up, checked for rips or tears, put it back together and it works as it should. ???  No crud from the tank and the tank filter was clean.

Pulled carbs, took the bowls off and everything is clean & working with no apparent reason for the floats to stick.

My questions are, do the float valves wear out and what would you replace?  They don't give them suckers away, $17 each

I'm sticking with the OEM petcock cause I like the chrome hangers.

I've got a bike with 115K on it and the carbs are stock except for the 38 slows and runs excellent, so why is this one with 40K bumming me out?

[97Valk_CT_Euless]

 I don't quite understand "two of them wouldn't, kept leaking gas".  Wouldn't stop draining?  WOuldn't drain at all?  Sorry, maybe I'm just dense...

[Hook#3287]

Yeah, sorry, I know what I meant

While draining, with the petcock in the off position, gas should stop once the bowl is empty.  Two carbs kept leaking gas out the drain tube which meant floats are stuck AND petcock has failed to shut off.

Perfect conditions for the dreaded Hydrolock.

[Ricky-D]

Yeah, sorry, I know what I meant

While draining, with the petcock in the off position, gas should stop once the bowl is empty.  Two carbs kept leaking gas out the drain tube which meant floats are stuck AND petcock has failed to shut off.

Perfect conditions for the dreaded Hydrolock.

No, that scenario does not mean the floats are stuck.

Only that the petcock is bad!

***

[Hook#3287]

No, that scenario does not mean the floats are stuck.

Only that the petcock is bad!

Okay, now I get it, when the float drops it allows gas to enter the bowl. as the gas rises the float rises closing the valve. Some reason I thought when the float dropped it shut the flow off.

Maybe from looking at it upside down on the bench.

Thanks for straightening me out on that.

But why only two?  It should have flowed from all.  It definitely stopped when the other four emptied.

[sandy]

Why only 2: The petcock isn't leaking fast enough to supply more than 2 carbs. Were the 2 in the rear or on the left side?

[Hook#3287]

Why only 2: The petcock isn't leaking fast enough to supply more than 2 carbs. Were the 2 in the rear or on the left side?

#5 and #2, Right rear and left middle, bike was upright.  It didn't matter what I did, if I left 5 or 2 open the gas would flow, all the other stopped after the bowl was empty.  If I opened say 4, when it stopped, if I opened 5 or 2 the gas would flow again.

I don't get it.

[Hook#3287]

opps 5 and 4

[indybobm]

I agree with you, all of the carbs should keep flowing if the petcock is bad. I think you have a bad petcock and 4 sticky floats. The two that continue to flow are working properly.

[Hook#3287]

I agree with you, all of the carbs should keep flowing if the petcock is bad. I think you have a bad petcock and 4 sticky floats. The two that continue to flow are working properly.

Well, that's something I didn't consider.  I took all the bowls off and saw nothing that would cause concern.  Nice and clean and the floats seemed to be working correctly.

So the 4 floats would have to be stuck in the high position?  Sounds crazy, but what else could cause the symptoms?

[Hook#3287]

So, as I'm draining each carb, 4 floats decide to stay up? 

Bike had sat for a couple weeks before I moved into my cellar.  I didn't start it when I moved it so it's been a month.

First chance I get, I'm pulling the plugs.


 

[The emperor has no clothes]

I agree with you, all of the carbs should keep flowing if the petcock is bad. I think you have a bad petcock and 4 sticky floats. The two that continue to flow are working properly.

Well, that's something I didn't consider.  I took all the bowls off and saw nothing that would cause concern.  Nice and clean and the floats seemed to be working correctly.

So the 4 floats would have to be stuck in the high position?  Sounds crazy, but what else could cause the symptoms?

Bill, I'm thinking its a leaking petcock. Possibly not leaking at full flow but just enough to flow to the 2 carbs. Just a guess though. Maybe it's flowing to those two because they are closest to the inlet (I can't remember if they are) I'm thinking if the float seats were bad you would have gotten fuel coming out the overflow line before this.

[Hook#3287]

I agree with you, all of the carbs should keep flowing if the petcock is bad. I think you have a bad petcock and 4 sticky floats. The two that continue to flow are working properly.

Well, that's something I didn't consider.  I took all the bowls off and saw nothing that would cause concern.  Nice and clean and the floats seemed to be working correctly.

So the 4 floats would have to be stuck in the high position?  Sounds crazy, but what else could cause the symptoms?

Bill, I'm thinking its a leaking petcock. Possibly not leaking at full flow but just enough to flow to the 2 carbs. Just a guess though. Maybe it's flowing to those two because they are closest to the inlet (I can't remember if they are) I'm thinking if the float seats were bad you would have gotten fuel coming out the overflow line before this.

Hey Rob;

Yeah, the petcock was stuck, I pulled it apart and it works as designed now.   Can't figure it out, except to what indybobm said, 4 floats stuck UP not allowing flow while the two that were working allowed the gas to flow from the stuck petcock.

Messed up, don't know what to blame so I'll go with the crap ethanol gas.

[The emperor has no clothes]

Oh I can relate to bad gas. I had to clean the carbs on my standard after letting it sit too long. The slow jets were the worst but everything needed cleaned.

[Ricky-D]

I don't think it's the floats need to stick up, but rather the needles need to stick. I would suggest to confirm that is the case before doing anything else. It seems unlikely that four float needles would all be sticking at the same time.

[Hook#3287]

I don't think it's the floats need to stick up, but rather the needles need to stick. I would suggest to confirm that is the case before doing anything else. It seems unlikely that four float needles would all be sticking at the same time.

Okay, I agree, it does seem unlikely.  Do you have any idea why 4 carbs drained and the flow stopped, while two continued to flow, while the petcock was stuck open? 

I have not inspected the needle jets yet, tomorrow after I pull the plugs to make sure none of the cylinders are full of gas, I'll will.

[indybobm]

Remember, this is gravity feed, not pressure feed. Pressure feed would overcome stuck needles/floats. Just a guess but it sounds good. I think it matches the symptoms.

[Michvalk]

It's the ethanol gas. Turns to crap really fast. I keep seafoam in mine all the time, just in case it sits for a little while. I run the stuff even in the summer, and give it a heavy treatment for winter storage

[Ricky-D]

Sure!  Entirely makes sense.

The petcock is the problem.  Because it didn't shut off.

There was not enough gas leaking from the petcock

to supply enough gas for all six carburetors to display

the leaking gas.  Only enough leaking gas for two

carburetors to display the leaking gas. If you turn the petcock

to full "on" you may possibly see the remaining four carburetors

display running gasoline, but that is not guaranteed. It is all

dependent upon the gasoline supply lines, the configuration, and

the incongruent assembly variations along with any minor

contamination issues that have accumulated over the years, such

as partially clogged fuel lines.

My suggestion. Continuously using gasoline additive, formulated

especially for problems encountered with using ethanol enriched gasoline.

***

[Hook#3287]

Yes, petcock was the problem.  Fixed.

Pulled the plugs and no gas in any cylinders, good.

Checked all needle valves and everything looked good, clean, nothing plugged, no rips or holes in the vacuum pistons.

I still can't get my head around why only two carbs would leak.  When the one's that continued to flow were shut off, I left the others open till they emptied and then some.  They would stop flowing gas. ???

Beats me, but thanks everyone for the help.

[Rocketman]

I don't see why it would be unlikely to have four stuck at once.  If they effectively soaked in old fuel for some period of time, some could easily get stuck and others not.  I would bet that they're intermittently sticking while you're riding, too.  If you open all the drains and the petcock (apply vacuum to that line on the back) and it doesn't flow out all six, you've got an issue.  There is no other way to get more fuel to flow to the floats.  Obviously four aren't stuck full time, or you would have noticed some lack of power, only running on two cylinders.  However, it could be sticking some, or it could get worse.  Some in-fuel cleaner ought to do the job.

On the petcock:  I know you say you disassembled it, and it works now, but not knowing what the issue was scares me a bit.  I think inspecting (or rebuilding/replacing) that thing is in order.

Mark

[Hook#3287]

I don't see why it would be unlikely to have four stuck at once.  If they effectively soaked in old fuel for some period of time, some could easily get stuck and others not.  I would bet that they're intermittently sticking while you're riding, too.  If you open all the drains and the petcock (apply vacuum to that line on the back) and it doesn't flow out all six, you've got an issue.  There is no other way to get more fuel to flow to the floats.  Obviously four aren't stuck full time, or you would have noticed some lack of power, only running on two cylinders.  However, it could be sticking some, or it could get worse.  Some in-fuel cleaner ought to do the job.

On the petcock:  I know you say you disassembled it, and it works now, but not knowing what the issue was scares me a bit.  I think inspecting (or rebuilding/replacing) that thing is in order.

Mark

Hey Mark;

Fuel wasn't old, about 1 month.

Bike runs excellent.

Can't do any more tests, cause the carbs are sitting on the bench.

I rebuilt the petcock last Feb., it was stuck when I opened it up, checked close, put it back together.  Probably gonna get a new rebuild set.

I've used Techron several times over the season, guess not enough.

I've carried Techron in my bags to use every time but the damn caps come loose and everything in the bags gets wet or smells, so I don't use it as much as I should, obviously. I even put it in zip lock bags and the caps still came off.

Wish they made a single use pill or bag that you could drop in the tank and be done.