airbox with fuel question

[DenyP]

Deny, I tested the tank petcocks while I had the tank off the bike. All positions worked as expected without leaking. The octi, however, I have no clue how to test.
Is there a way to test the octi by itself?

Vent T's are clear and unobstructed.

My thought process focused on the gas filling the bottom of the air box. If it was just a needle valve with the pet cock working correctly there shouldn't be that much gas (just what is available in the line(s)) I agree with what others have said about the needle valve should work regardless of the pet cocks/octy. If this was a reality however bikes wouldn't have fuel shut off valves. JMHO

Deny

[cywelchjr]

My thought process focused on the gas filling the bottom of the air box. If it was just a needle valve with the pet cock working correctly there shouldn't be that much gas (just what is available in the line(s)) I agree with what others have said about the needle valve should work regardless of the pet cocks/octy. If this was a reality however bikes wouldn't have fuel shut off valves. JMHO

Deny

If what you say was true there wouldn't be shutoff valves for house water or for sink faucets. It's basically an emergency shutoff, or in the case of most bike, something to allow the tank to be removed to allow maintaining the bike without the gas from pouring all over. The needle valve should still never let anything get past it unless something is wrong with it.

That said, any time you get gas in the airbox, you have at LEAST two things wrong, one or more needle valves wrong, and a bad petcock or octy.

[Redshirt]

Fixed!!!.....???

The floats passed the hot water test. No leaks. While I was in there I checked the seats and needles. The seats were "slightly tighter than hand tight". I wrenched them, but so gently that I think it wasnt making a seal.
Tightened them down and put it all back together. I monkeyed with the octi too, reseating the components.
I think gas was bypassing the valve through the loose seats causing the overflow. I took it for a 50 mile ride and parked it on RUN. Not a drop is apparent.
I will keep an eye on it though. Thanks for all the suggestions and information. It was helpful.

[DenyP]

If what you say was true there wouldn't be shutoff valves for house water or for sink faucets. It's basically an emergency shutoff, or in the case of most bike, something to allow the tank to be removed to allow maintaining the bike without the gas from pouring all over. The needle valve should still never let anything get past it unless something is wrong with it.

That said, any time you get gas in the airbox, you have at LEAST two things wrong, one or more needle valves wrong, and a bad petcock or octy.

Cy,

If what you say were true, why go to the trouble of making pet cocks with auto shut off (vacuum actuated). Kliene carbs on a 80 kZ750 wouldn't have bowl overflow tubes! But of course who am I to offer assistance with a garoo here!

Deny

[natemoen]

Cy,

If what you say were true, why go to the trouble of making pet cocks with auto shut off (vacuum actuated). Kliene carbs on a 80 kZ750 wouldn't have bowl overflow tubes! But of course who am I to offer assistance with a garoo here!

Deny

considering the possible concequences of float bowls overflowing (ie washed cylinders, spun bearings......) the more possible items put in place to prevent those blows from overflowing the better. So yes, you could get by with just the floats but you better change those needles and seats each year so they stay perfect otherwise you might have a problem, or maybe they will be fine for a decade or three you just don't know. As to the auto shut off on petcocks (or even the octy), again people forget to turn petcocks off, why not make it so the don't have to remember and they shut off on their own.

Things inevitably fail, the less chance that the is a total failure of the whole system the better, so 2 or 3 items that do a job gives more safety.

[cywelchjr]

considering the possible concequences of float bowls overflowing (ie washed cylinders, spun bearings......) the more possible items put in place to prevent those blows from overflowing the better. So yes, you could get by with just the floats but you better change those needles and seats each year so they stay perfect otherwise you might have a problem, or maybe they will be fine for a decade or three you just don't know. As to the auto shut off on petcocks (or even the octy), again people forget to turn petcocks off, why not make it so the don't have to remember and they shut off on their own.

Things inevitably fail, the less chance that the is a total failure of the whole system the better, so 2 or 3 items that do a job gives more safety.

Exactly, it's about having multiple points of protection rather than a single point. Since a failure has such high cost you put as many things in the line for protection as you can. So my opinion is, keep as many of them in the line and working as you can. Now I'd add the positive off position to the standard petcocks as well, it's yet another protection.

[Bonz]

I may be out of turn or out of my "element" here, as I have an 80 SG Special, with which I am very familiar with this problem, or so it would seem from what you describe.

I went through these same exact processes of "what could it be" last summer when after syncing the carbs, I had fuel dumping into the airbox after I would shut it down after riding. I'm thinking to myself "why would syncing cause something like this to happen"? Ultimately, there was no connection to the sync, per se, which a sync in and of itself wouldn't cause what was happening.

Checked the petcocks, checked the Octy, all that was good. Carbs were clean (I knew they should be 'cause I had cleaned them recently), needles were seating with the carbs off the bike (no leaks),but despite everything checking out, nothing made sense.

Bought some carb rebuild kits from GeorgeFix, which included new needle seats w/o-rings. My old needle seats would go in with very little friction (the push-seat type, not screw in seats) and the new ones were hard to get in, as they had a very nice tight fit.

So, I think you may have found your culprit, in the needle seats not being tight. Sounds like you tightened them down, and with it not leakng as per your last post, I'd bet a $1 that you have your problem solved. Wish I'd seen this post a bit sooner, and I'd have chimed in and directed to check it out.

[DenyP]

If what you say was true there wouldn't be shutoff valves for house water or for sink faucets. It's basically an emergency shutoff, or in the case of most bike, something to allow the tank to be removed to allow maintaining the bike without the gas from pouring all over. The needle valve should still never let anything get past it unless something is wrong with it.

That said, any time you get gas in the airbox, you have at LEAST two things wrong, one or more needle valves wrong, and a bad petcock or octy.

Cy,
If you re-read what I was saying you will find we are not in disagreement regarding this problem. You don't need to be a self important jerk or prick when you disagree with another member. Do this to a new guy and he is gone. Our purpose in having this organization is to try to help one another - not see who can be king of the hill! I am NOT impressed!

Deny

[CaptonZap]

Cy,

But of course who am I to offer assistance with a garoo here!

Deny

But of course who am I to offer assistance with a garoo here!

Deny

Uh, Deny, what kind of not being a "self important jerk" is that remark about?

Or, as The Old Philosospher used to say, "We see in others what we have inside our selves".

CZ

[DGXSER]

Easy folks, its just a MC forum. No one gets paid or kick backs for their advice that works out or not.

It is easy to get wrapped up in this stuff. I have fallen into the trap myself before, and may again. But reality is that everyone here is trying to be helpful to all. it is unfortunate that some folks do try to make their opinions the only right ones at times, reality is that it is all just opinions.

It is way to easy to misread intent in this email-ish method of comunication. I will say that some of it does tend to come across like "Listen here you stupid whiper snapper" or perhaps "now that the bafoons have spoke there stupidity, let ME tell you how it REALLY is" sometimes. Well, I met a very old carpenter when I was a very young carpenter. He used to have that attitude. Until he was sawing off a roof rafter from the wrong side of it. A young fellow tried to tell him, but he would not listen, he had done this so many times no young inexperienced person could tell him how to do it. A broken nose, cheek bones, and collar bone later, he listened to anyone with a point to make about anything. A lesson I find myself referring back to as the years behind begin to surpass the ones I see in front of me.

[Bonz]

Well said.

With that said, I don't necessarily believe that if fuel gets in the airbox you have to have at least two things wrong.

It's a simple thing for the bike to have a bad needle seat seal like I described in my last post, and for fuel that is already in the float bowl to come back out into the airbox until the fuel level in that carb has gotten lower via the leak.

Seems like the original poster found his problem, and IMO it was his needle seats needing to be snugged up, and only that.

Capton Zap and I discovered that as well when I rebuilt my carbs last fall, that the needle seat o-rings in my SG were the culprit, nothing else was wrong.

[Redshirt]

Id like to add that I do appreciate everyone discussing the possible causes to the problem. It helps us less experienced learn of various aspects that we are unaware of.
With the inherent limits of forum communication, troubleshooting by this means can diverge to areas that are related, but may not be the exact problem. Still the lessons learned are valuable to people like me. What is important is getting our rides on the road safely.

Day 2 of riding after tightening the seats and I have not had a repeat of the overflow problem. Hooray?

[Bonz]

I don't think you will have any more problems related to seats, good job on getting the right thing fixed, and good job on being patient to find the root cause.

[DGXSER]

The true test in my opinion is to turn the petcocks to on, and let the bike sit for about 3-5 minutes. If you have the octy, then pull the vacuum hose off and apply a vaccum to it and wait that same 3-5 min.

Basically put all the work on the needle valve seats to hold back the fuel. If they do that for 3-5 minutes. Then they are working properly. If you can disconnect the fuel lines and no fuel flows from the petcocks in the off postion, your petcocks seem to be working fine.

Generally speaking, I think you have found and cured the problem. You should be good to go for a long time.

[Redshirt]

I let the petcocks stay on all day after I put it back together yesterday. But, as a precaution, I shut the petcocks off at night. Even after hours of letting it sit with petcocks left on, no apparent leaking into airbox.
I havent tried the test with the vacuum you mention. Its raining right now, and I dont have a garage, so it will have to wait.