flooding/petcock issue

[kevsgs]

I am thinking it is possibly the petcock since the bowls are getting gas or running without overflowing depending on where the petcock is positioned. Today I'm going to put it all back together and hook up airbox and see if this helps as far as it getting to bowls full while on ON position, still have no idea what happened there as it was doing fine for a bit, then just quit filling the bowls unless you let it sit for a minute or turn to PRI. Would love any suggestions.

[banditom]

On vs prime

Since you said it just wont flow on ,,,,,ON,,,,,,,, but will flow on prime, I would be checking that vacuum line first thing, I think you already said you have a new one, be sure everything is attached correctly and its not bent off and closed due to the tuning efforts. The next thing, would be the source of vacuum, which is the number two carb, right,??? Did your tuning do something that would stopper off the source of vac to the petcock. The only thing I think that would do this, is a wide open throttle, but that is a very long shot if youve had the bike running. Is it possible for a diaphragm leak to affect the vacuum to that source????


Here is hoping youve got a kinked off vac line to make it easy for you.

Since no one has mentioned this, except for cliff alluding to it, if this overflow continues, you may want to pull the floats, if they are plastic, check for casting flash on the sides of them, take the flash off with a file. Also, Ive heard of oversized carb bowl gaskets interfering with float operation, it may be best to trim them back with a scissors if there is more than say, a steenth of an inch of overlap into the float bowl area. I do this routinely when having the carbs apart on a new to me bike, but have never actually experienced the problem itself.

Fuel flow when its not supposed to,, is very dangerous, if that bike is kept in an attached garage, woe be to anyone sleeping in the house if it starts leaking and a source of ignition is present. Ive also read of a guy going down the road on a gas leaking bike, and the thing caught fire while he was still riding it, he was fortunate he didnt end up with toasted gonads on that deal. I personally had an xs eleven that had a leak that I couldnt find, it turned out to be an opening that I had forgotten to close, it was very scary but there was no source of ignition so all was ok. I also had a car backfire, and literally lite the throttle body on fire, I can tell you there was some mad dashing looking for a way to put it out before I finally smothered it with an old tee shirt. To this day, there are melted looking plastics on the throttle body, but the car runs just fine with it like that.

[kevsgs]

Since you said it just wont flow on ,,,,,ON,,,,,,,, but will flow on prime, I would be checking that vacuum line first thing, I think you already said you have a new one, be sure everything is attached correctly and its not bent off and closed due to the tuning efforts. The next thing, would be the source of vacuum, which is the number two carb, right,??? Did your tuning do something that would stopper off the source of vac to the petcock. The only thing I think that would do this, is a wide open throttle, but that is a very long shot if youve had the bike running. Is it possible for a diaphragm leak to affect the vacuum to that source????


Here is hoping youve got a kinked off vac line to make it easy for you.

Since no one has mentioned this, except for cliff alluding to it, if this overflow continues, you may want to pull the floats, if they are plastic, check for casting flash on the sides of them, take the flash off with a file. Also, Ive heard of oversized carb bowl gaskets interfering with float operation, it may be best to trim them back with a scissors if there is more than say, a steenth of an inch of overlap into the float bowl area. I do this routinely when having the carbs apart on a new to me bike, but have never actually experienced the problem itself.

Fuel flow when its not supposed to,, is very dangerous, if that bike is kept in an attached garage, woe be to anyone sleeping in the house if it starts leaking and a source of ignition is present.

I was just about to put the carbs back on, but I think I will open up the bowls again and take a look at those floats. They are not leaking and they float great, one of the first things we checked. However I have not checked for any casting flash or overlaping gasket, so I'll check that real quick before re-installing. The problem now does seem to be vacuum related so I will also make sure nothing is blocking the line or anything wierd there. I also plan on puting in an inline shutoff to know for sure the fuel is turned off when not in use. Don't think its necesary but like you said I don't want to take that chance as it is an attached garage. When the tank is off and currently half full of fuel there is absolutely no leaking though, but better to be safe. I'll go try these things and see what I come up with....thanks.

[banditom]

be sure to let us know what cures it

be sure to let us know what cures it

[kevsgs]

Well went through and checked the floats, nothing that they would be catching on. I've even got the back tang set so that the bowls cannot fully make contact when they are at their lowest level just in case they were getting caught there. Put it all back together in hopes of something working itself out, (because that always happens right? ), but it is still doing the same thing. It fires up, runs and sounds smooth, especially with airbox connected again, but it dies as soon as it burns through whatever fuel was in the bowls. I have to turn it to PRI to fill the bowls again. So at this point I'm thinking its got a bad petcock. The vacuum is not allowing the fuel to flow through the petcock. I did look at the vacuum line, looks perfect, no obstructions, even with tank on there is nothing pinching or kinking the line. I'm wondering if I try taking it apart again if I can figure out something, the spring on the vacuum side of petcock for the diaphram felt nice and strong and worked properly when we tried it. The petcock is the last part of that system that is not new, I don't know, I guess I'll go pull it apart and see what I can see. Again any advice or suggestions are very welcome!

[GateKeeper]

put a long clear hose, onto the vacuum line and suck....I know that don't sound right, but you know what I mean,,,,,,as in your acting as the vacuum, and see if you can get fuel to come into the feed hose.....

please use a long piece of hose, I don't want you to suck in fuel, that would not be a good thing

[kevsgs]

put a long clear hose, onto the vacuum line and suck....I know that don't sound right, but you know what I mean,,,,,,as in your acting as the vacuum, and see if you can get fuel to come into the feed hose.....

please use a long piece of hose, I don't want you to suck in fuel, that would not be a good thing

I just pulled off the tank and went to drain it to maybe take a look at the petcock, and I actually did just that. With a tube draining the gas into a can, i hooked the vacuum line up and sucked on it, (yes that does sound funny,lol, but whatever she needs to run,lol), no fuel would flow while in the ON or RES position until I sucked on the vacuum line. And of course on PRI it just free flowed as it should. A couple things seemed a bit wierd to me but I don't know a whole lot, I did have to suck pretty hard to get the fuel flowing. The second thing was as it got towards the last of the fuel a lot of air was going through the line with the gas. Should I have to suck that hard to activate the vacuum, and should there be a lot of air bubbles flowing with the gas towards the last of the tank?

[kevsgs]

I'm obviously not getting enough vacuum to make the petcock open up and allow fuel in, would that be a bad petcock or something else?

[GateKeeper]

I am no expert on these things, the petcock, but perhaps the diaphragm is shot, or in backwards, or something to that effect ? I don't think it should take a whole lot of vacuum...?

[kevsgs]

I am no expert on these things, the petcock, but perhaps the diaphragm is shot, or in backwards, or something to that effect ? I don't think it should take a whole lot of vacuum...?

Well that is definately the problem, its not opening up the valve to let fuel in, so I'll go take it apart and see if I can fix it. It did seem to have to have a whole lot of suction to get it to work. While I'm messing with that I think I'll put the carbs back on the bench test and make sure they are still doing what they are supposed to as well. This is all very frustrating...something should have worked by now. I guess besides learning about carbs I'm also learning more patience.

[kevsgs]

I'm just at a loss

I put the carbs back on the bench with the temp tank hooked up, and they immediately started overflowing again. I put in brand new OEM valve seats and needles and O-rings, they should not be overflowing at all. AHHHHHHHH!!!!!! This is ridiculous!

[banditom]

prove the vacuum at the hose

Have you proven that there actually is vacuum at that hose thats sposed to open the ,,,,,,,,,,ON,,,,flow thru it. If you have a vac gauge, it would be good to see what the vac level is there. When I mentioned diaphragm, I was thinking the carb diaphragm, and the question was, ,,,,,,if there was a problem with the carb diaphragm, maybe being out of place or leaking, does that affect the vacuum at that vacuum line that opens the petcock.

Regarding the overflow,,this is a longshot,,, is your temp tank,, at a similar height compared to what the reg tank would be if the carbs were on the bike. I am thinking maybe there is excess headspace here, putting the column of fuel higher than it would be under normal circumstance and putting more fuel weight on the needles and seats. The reason I think headspace could be a problem, is that my gk eleven runs less well with only a quarter tank of gas, if I go fill it up, it seems to run better.

I also have to ask, are the new needles and seats, identical to the old ones visually, because if I am reading this correctly, youre suggesting that the new ones overflow quicker and harder than the old ones. The difference could be the headspace thing, or the WRONG parts if I dare say so.

[sedelen]

There's a little check valve inside the petcock for the vacuum line. Perhaps it has dried out or has dirt in it making it hard to operate, maybe shoot some WD-40 down inside the tubing and work it free.
It shouldn't take much vacuum to operate it.

[kevsgs]

Have you proven that there actually is vacuum at that hose thats sposed to open the ,,,,,,,,,,ON,,,,flow thru it. If you have a vac gauge, it would be good to see what the vac level is there. When I mentioned diaphragm, I was thinking the carb diaphragm, and the question was, ,,,,,,if there was a problem with the carb diaphragm, maybe being out of place or leaking, does that affect the vacuum at that vacuum line that opens the petcock.

Regarding the overflow,,this is a longshot,,, is your temp tank,, at a similar height compared to what the reg tank would be if the carbs were on the bike. I am thinking maybe there is excess headspace here, putting the column of fuel higher than it would be under normal circumstance and putting more fuel weight on the needles and seats. The reason I think headspace could be a problem, is that my gk eleven runs less well with only a quarter tank of gas, if I go fill it up, it seems to run better.

I also have to ask, are the new needles and seats, identical to the old ones visually, because if I am reading this correctly, youre suggesting that the new ones overflow quicker and harder than the old ones. The difference could be the headspace thing, or the WRONG parts if I dare say so.

I put the carbs back on the bike after another succesful bench test, and with them hooked into the gas tank while on PRI it still overflowed the carbs. Started up the bike and kept it running while playing with the petcock to keep bowls with gas but avoiding overflowing, and pulled the vacuum line to feel how much vacuum it had. It should have had plenty to open up the fuel line. Then turned off the motor and filled the float bowl with fuel, then ran a clear line from the petcock for the fuel into a can, and hooked up the vacuum line, started the bike to see how much fuel it is pulling and it barely was pulling any, it was just barely tricklin out. Which explains why when its in ON position I'm just burning through the fuel in the bowls then it dies.

[kevsgs]

I also have to ask, are the new needles and seats, identical to the old ones visually, because if I am reading this correctly, youre suggesting that the new ones overflow quicker and harder than the old ones. The difference could be the headspace thing, or the WRONG parts if I dare say so.

The parts were OEM from suzuki.