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Just a few of my thoughts... I looked at my gas cap and tank as I have them off the bike and in the house. Mine is a non Cali model. I do have a little nipple that is on the underside rim of the gas cap that presses into the little hole when cap is closed. I have no rubber insert in the hole. There are two little holes in the underside of the cap and your cap too. Is it possible that blockage is there. Also, do the caps actually seal all air from getting into the tank? I think not, and may be wrong. But, if no air in then a vac would form in the tank.. So, if some air gets in from the cap, is it possible to simply cap or get rid of all extra Cali lines and kind of convert the tank. This might be dangerous... but, just thinking. Also, I have never filled my tank with gas to any closer than a inch or so of the neck.
 

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Just a few of my thoughts... I looked at my gas cap and tank as I have them off the bike and in the house. Mine is a non Cali model. I do have a little nipple that is on the underside rim of the gas cap that presses into the little hole when cap is closed. I have no rubber insert in the hole. There are two little holes in the underside of the cap and your cap too. Is it possible that blockage is there. Also, do the caps actually seal all air from getting into the tank? I think not, and may be wrong. But, if no air in then a vac would form in the tank.. So, if some air gets in from the cap, is it possible to simply cap or get rid of all extra Cali lines and kind of convert the tank. This might be dangerous... but, just thinking. Also, I have never filled my tank with gas to any closer than a inch or so of the neck.
Yes, if the tank is airtight, you get POOGS.

If the Cali gas cap is the same as all others, there's a check valve and liquid separator inside the cap. See Step II parts11 through 17 at the link below.

Kontiki' s cap is seeping liquid. Maybe?




I suppose checking gas cap part numbers would answer the question.

Edit: Yes, it looks like all gas caps are the same. The cap is not listed in the cali emissions evap system schematic. One part number in the Fuel Tank schematic.

I would strip the gas cap and check it.

Parts List

 

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2001 Kawasaki Vulcan 750
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Discussion Starter #23 (Edited)
Yes, if the tank is airtight, you get POOGS.

If the Cali gas cap is the same as all others, there's a check valve and liquid separator inside the cap. See Step II parts11 through 17 at the link below.

Kontiki' s cap is seeping liquid. Maybe?


I suppose checking gas cap part numbers would answer the question.

Edit: Yes, it looks like all gas caps are the same. The cap is not listed in the cali emissions evap system schematic. One part number in the Fuel Tank schematic.

I would strip the gas cap and check it.

Parts List

[/QU
So I am doing more research, because there are no used caps to be found unless I buy a whole used gas tank not gonna do that. New caps don't come with lock tumbler. I see that I should be able to remove my old tumbler by pressing the locking pin and pulling it out. I stripped the cap down and could see the pin, but I can't get it pressed in, so I need a locksmith or check if my dealer can do it.

My cap all passages were perfectly clean from the rebuild I did on my initial restoration a few months ago. No trace of POOGS whatsoever of course. The ONLY thing unusual about it is the check value was stuck and couldn't be removed but could see that the four holes under the orange diaphragm were perfectly clear and could blow air thru. Oh well.. its worth $92 + tax to get a peaceful feeling with no gas spouting out, if it would fix it.. Kinda chapped if I have to pay a locksmith however...

And I can't believe this frickin' thing is able to find a path to put gas under pressure and route it up the vapor vent hole and up and out the cap key hole.

I'm gonna run some more tests. I know there are two passages inside my tank: vapor vent out and gas return from the separator valve. I had connected the two at the back of the tank with a rubber hose to eliminate the vapor system entirely.

So now instead I will run a hose from each to a catch bottle like we used to do on our race bikes. See what I get. Let you know later...
 

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2001 Kawasaki Vulcan 750
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Discussion Starter #24 (Edited)
So I am doing more research, because there are no used caps to be found unless I buy a whole used gas tank not gonna do that. New caps don't come with lock tumbler. I see that I should be able to remove my old tumbler by pressing the locking pin and pulling it out. I stripped the cap down and could see the pin, but I can't get it pressed in, so I need a locksmith or check if my dealer can do it.

My cap all passages were perfectly clean from the rebuild I did on my initial restoration a few months ago. No trace of POOGS whatsoever of course. The ONLY thing unusual about it is the check value was stuck and couldn't be removed but could see that the four holes under the orange diaphragm were perfectly clear and could blow air thru. Oh well.. its worth $92 + tax to get a peaceful feeling with no gas spouting out, if it would fix it.. Kinda chapped if I have to pay a locksmith however...

And I can't believe this frickin' thing is able to find a path to put gas under pressure and route it up the vapor vent hole and up and out the cap key hole.

I'm gonna run some more tests. I know there are two passages inside my tank: vapor vent out and gas return from the separator valve. I had connected the two at the back of the tank with a rubber hose to eliminate the vapor system entirely.

So now instead I will run a hose from each to a catch bottle like we used to do on our race bikes. See what I get. Let you know later...
UPDATE:
No more vapor emission stuff, both lines from tank going to catch bottles.
53116

Catch bottles don't catch any gas, so the tank is not forcing liquid gas out.

[Spockster if you see this, it would look better with a chrome coolant tank cap do you still have one?]

But guess what, now I have POOGS! Quit on me on the freeway had to get through right lanes to shoulder and scope it out while 85 mph traffic going by a few feet away. [SEEMS TO BE SOLVED: Drilled vent hole in top of catch bottle.]

Died in town when I hit a stoplight, very lucky no traffic behind me, pulled out key, opened gas gap and it started with cap open luckily.

Burned thru a full tank (not topped up) to reserve in just 95 miles, result of cruising at 6,000 rpm for about 60 mi.... we need a) bigger tank but it wouldn't be as sexy as what we have now b) better gas mileage -- it could use a 6th gear it's a bit too high to be using 6K rpm on a v-twin cruiser.

So, when I had bad POOGS and wouldn't restart, I pulled the vapor out line from the tank out of the catch bottle and heard it release pressure. It was creating a vacuum in the bottle, no atmospheric pressure venting into the tank so gas couldn't be be released into carbs... guhhhh!!

I'll stop messing around with this and put on a brand new cap and see what happens. And I will also put back the vapor emission (return separator pump and charcoal canister - they don't have any effect on horsepower and if they keep gas smell out of my carport its a good thing, plus they hopefully are designed properly so they let the tank vent no more POOGS which i never had before.)

BTW the Gas Cap part number changed from 2001 to a different one for the end-run to 2006. So who knows maybe the engineers listened up to our mis-adventures and improved both the venting in (POOGS) and seals (leaking). Yeah, sure!

So, this is still not resolved. More later..
 

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Sorry I just saw this thread, but I had this happen on my bike. I fixed it by replacing the two O rings under the two screws that held the gas cap to the tank.

I only skimmed the thread, so I apologize if this was already tried.
 
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