Gas cap seepage-- Need help

[bobhamlin]

Took the newly-legal Nomad out for its first enjoyment ride (as opposed to commuting)

I filled up with gas (bike on the side stand, filled to the level of that metal bottom of the gas opening).

As I was driving, I smelled gas, then noticed that gas was seeping, pretty heavily, from under the gas cap. Two thoughts (Well 3 actually).

WTF?
Gas dripping down on the engine and pipes is not good.
My new paint job!!

This is my first FI. I know the tank is pressurized, but what causes gas to defy gravity?

It stopped after I burned off about 1/3-1/2 gallon. For almost 1100 miles, I've filled the bike the same way and never noticed leakage before. But half of my driving has been in dark so I might not have noticed it. Most of my driving has been at highway speeds, so I might burn through the 1/2 gallon quickly.

When I noticed the leakage, I was driving in town: stops, starts and up to 40 mph.

Help?

[rewindgy]

Nope - probably just missing the o-rings either under the two screws that hold the gas cap to the tank or as in my case - the o-ring that fits between the overflow nub on the tank and the under side of the gas cap. Good news - they are only $5.00 o-rings - the bad news - why the H ll can't Kawi remember to put them in?

[bobhamlin]

Originally Posted by rewindgy

Nope - probably just missing the o-rings either under the two screws that hold the gas cap to the tank or as in my case - the o-ring that fits between the overflow nub on the tank and the under side of the gas cap. Good news - they are only $5.00 o-rings - the bad news - why the H ll can't Kawi remember to put them in?

You nailed it!!
It was that o-ring. I can't blame Kawi or the dealer though. I took the cap off to get the tank painted and thought I was being oh-so-careful. That O-ring is either laying on my garage floor somewhere or -- gulp-- in the tank.
Monday, I'll order another.

Thanks a lot.

[glwilson]

Mine didn't have one either...

Do you know if that is just a standard type of 0-ring?... something I can buy at the hardware store? I would assume so.

[blowndodge]

I'm guessing that is not the case. My tank leaked like a seive until I fixed the cap. I thought maybe a gasket was bad or missing but that wasn't it. If you have a gasket underneath the cap that seals the opening of the tank, thats the only place it would leak. I don't have any other gasket sealing any other hole under the cap except the tank opening itself.

Mine had pressure build up because of the venting mechanism under the cap. I had to dissasemble the cap and fix it on my own because MaKaw wouldn't do it.

[Top Cat]

Originally Posted by Blowndodge "Darksider"

I'm guessing that is not the case. My tank leaked like a seive until I fixed the cap. I thought maybe a gasket was bad or missing but that wasn't it. If you have a gasket underneath the cap that seals the opening of the tank, thats the only place it would leak. I don't have any other gasket sealing any other hole under the cap except the tank opening itself.

Mine had pressure build up because of the venting mechanism under the cap. I had to dissasemble the cap and fix it on my own because MaKaw wouldn't do it.

Same here.

[bobhamlin]

Originally Posted by Blowndodge "Darksider"

I'm guessing that is not the case. My tank leaked like a seive until I fixed the cap. I thought maybe a gasket was bad or missing but that wasn't it. If you have a gasket underneath the cap that seals the opening of the tank, thats the only place it would leak. I don't have any other gasket sealing any other hole under the cap except the tank opening itself.

Mine had pressure build up because of the venting mechanism under the cap. I had to dissasemble the cap and fix it on my own because MaKaw wouldn't do it.

Now I'm as confused as when I started the thread. There IS an O-ring in the parts microfiche. I don't have one. If there was an O-ring, I probably lost it somewhere duing disassembly/reassembly of the tank.

What can be "fixed" in the gas cap?

Finally, how is gas blowing uphill? I thought the purpose of the pressure was to make sure it squirted out the gas line at the bottom of the tank.

I thought FI was going to be difficult because of the precision required during injection, not because of a gas cap.

[glwilson]

Bobhamlin:

I will wait to see how to fix this as well as I have leaking also - but only if I fill the tank right up to the bottom of the strainer. If I stop a half to quarter inch short of that -- I don't seem to have problems. If the gas touches it... I have leaking.

I know BD and others discussed this sometime last year... but I would still like to hear about the solutions; because either way... it is a pain to have gas running out onto the tank.

[blowndodge]

High pressure builds up because of heat from engine and/or air temp outside. If you had a hot bottle of coke and the cap leaked and you drove down the highway with it on your rack (Think of your gas tank vibrating away) it would leak out the top too.

When I would fill my tank anywhere near the splash guard I'd end up having gas all over my legs and tank and when I would park the bike I could see about a half cup of gas dripping on the ground.

It took forever but I found out that the venting mechanism on the gas cap wasn't letting the pressure out properly. If you fill your bike and ride it until you see gas leaking again, stop immediately and open the tank and I'll bet the cap opens us with a loud SWOOSH! Mine did until I fixed it.

http://kawanow.proboards77.com/index...ad=2590&page=2

[rewindgy]

Most people are missing the: Seal, Fuel tank Part # 92093-1030. It is supposed to seal the pressure overflow from the cap to the tank itself. ie. you cannot fill the tank over the cup inside the filler or it leaks out. I had one of the two O-ring, ID-9 Part# 92055-1552 split so tank was leaking all of the time. So when I fixed it, the leak only slowed down and would happen when I filled over the bottom of the cup. The seal is not an o-ring but a tapered rubber seal and you need to get it from Ma Kaw.

[blowndodge]

After fixing my cap I could fill up to the very top with no leakage.