Something I noticed only once last year, but two more times so far this year. Last week, I walked out to retrieve something from my tank bag and heard a hiss or slight whine from the tank. I then waited a few more minutes and it did it again. Its definitely powering something in the fuel circuit not just a mechanical venting. Not wuite the same as when you turn the key and it primes the pump, but close. Also IIRC, that morning I had filled up with fuel (or the day before); so it was near full.

I'm guessing it may have to do with the emissions controls for venting in the tank as it expands with temp changes? The bike had been off for a couple of hours, but was fairly cool when I rode home from work (midnights) and it was getting warmer. maybe a change in temp from 45-50 to 70 when I heard it. I then opened the tank fill, and it did let off a bit of pressure; didn't seem to make any more noise after.

anyone else notice this? Are we sure this is normal? how often should it purge pressure? and do I have to worry about it killing the battery?

Now I'm freaking out about it being the reason my battery was dead last fall. Constant drain, instead of something that's normal. Thoughts?

I then opened the tank fill, and it did let off a bit of pressure; didn't seem to make any more noise after.

Now I'm freaking out about it being the reason my battery was dead last fall. Constant drain, instead of something that's normal.

So WATT I'm saying is the AMPS are not going to be that high in the VOLTS. And without charging that bike that long sitting? Not good. So if it was current draw, that battery would be dead in a week. Only current draw is memory for the ECU and how much we talking? Something like 2ma or less?

* Last updated by: Hub on 6/13/2013 @ 2:21 AM *

my tank does it also. It seems to do it more when I ride a lot. Mean the fuel leaves faster and causes a vacuum. I will open the fuel cap and close it back up when I do hear it.

Gas vapor expands/contracts. For every expansion there is I'm not trying to be a wize guy, but I'd run down the neighborhood and release all my neighbor's car's tanks too. If it's closed loop, you breathed thru a charcoal canister so you do not breath that raw vapor. Now, you expose it so it is not filtered to atmosphere? Aren't you defeating the whole purpose of closed loop?

Ever see/use/blowup/sit on a whoopee cushion? Ever blow up a balloon and expand the rubber so the air sings thru the rubber ripples? That's the same rubber flapping, you go napping and it wakes you up it's that loud. Go back in the house and leave the bike alone.

Go back in the house and leave the bike alone.

Thats funny Hub...and good advice !!!

Pretty common, especially on the hyper-bikes ....

As long as she runs good, dont worry about it ...

Hub, I ride every day its not raining when I leave for work, or going to be when I come home. I do have a short commute, however. 6 miles each way. so 3700 miles on the bike from may to October, last year. Another 1250 this year, since may 1.

The period last fall when it was dead (battery) in the drive, it had sat for about a week, less than 10 days. If its more than that, I charge it with an automatic charger. Ive never had a bike go flat that quick, usually 30 days or more. My 03 R1 sat all winter the first year and never failed to start. I realize that bike may have had less drain from the ecu and such.

The noise is def an electrical, purge, hissing noise. Like something powers up, it goes vrrrrpppp (faintly) for about a second; then stops. When I noticed it this time, it repeated after another minute or so.

I understand the basics of the closed evap system for not venting tank pressure to the atmosphere. I just wasn't sure if it was a mechanical pressure valve or electrical type system that draws on the battery. and if it is electrical, how often should it run? (as needed, I get it. lol). The only reason I opened the tank, was to determine for sure if it was an evap circuit or the pump trying to power up with the key off.

An important thing to note. When I took the battery out last fall (dead), I found it was loose on the negative connection. Back then, I had assumed the noise I might have heard was just it breaking connection as I was washing the bike, and jiggling it a little causing it to reprime the pump as it regained connection.

That's not the case now, and basically I want to be sure its not something that's running TOO often, and making a problem. Ill keep an eye on it.

Plus, since I had to rip apart the body work to replace the battery (last fall); I have my charger hookup accessible. much easier to deal with a drained battery (if it happens again).

Thanks for your guys thoughts. Just wanted to see if mine was the only one that made hissing noises when sitting. lol.

* Last updated by: rod442 on 6/14/2013 @ 1:41 AM *

rod,

1250 a year divided by 12 months = 104 miles a month.
Say Yuasa uses 1% of current draw a day as a gauge = 1 month sitting is 30% down.

Buy looking at the mileage and the sitting time, I think a battery is looking to be replaced soon. I wouldn't gauge some other bike's battery in the same sitting situation. I'm just saying, because I asked about mileage vs. charge, there seems to be a normal pattern to this low mileage current draw vs riding time to recharge.

And like I said, a phantom current draw on its own making noise is totally different than hearing the tank expand and contract. That battery would be dead from that is my guess? And I was wrong about staying in the house. You need to get out of the house and ride more...

Every Kawi I have owned sings at me when it's not running. It's calling me to go ride it more. :)

Seriously, it is just the tank venting. Don't worry about it.

When I park my bike outside in the sunlight it will sing a Spanish concierto for me. Sort of like a tea kettle letting off steam.

Crack open the filler cap and park yourself by the bike with a cold beer and ponder life for a while. If the sound never again occurs then chalk it up to excessive pressure venting from the tank. If you continue to hear the hissing while the fuel cap is open then it's time to start searching for the power draw.

And more beer.

I have also heard this....on both of mine...2012 and 2013.HOWEVER...my 2012 did not have a purge valve setup(?).It may very well be the purge valve doing this at different times with the ambient temps changing.Once she(2013) was sitting in the garage....it was about 2 in the morning...I went out for something...I heard this 'noise',only for a second or so...then no more.I thought it was a bit odd cause non of my 14's ever vented unless they were being ridden or the engine had been heated up(heating up the tank).And I've 'caught' her doing this thing once in a while...just sitting.Not a long deal...just a few seconds.It must be normal....nothing goes wrong...the battery(a Shorai)is working just fine....no tending needed yet.Starting power is good.IDK IF the 2012's had this evap system on there?I don't remember mine having one.My 2013...yes...it does.

GRN14: My 2012 vents once in a while. If I dont want to hear it I pop open the gas cap and it all dissipates quickly.
My 2006 ZX14 did the same thing and neither has had any battery problems.

Here is what happens if you do not hear the tank breath, hiss, scream in the dark. OK? We done? Come on back in the house. Watch your step. There ya go. What's in the fridge? Seen I'll take a ham samich and what's that, beer? Lite? Shake the can up. I wanna show you something about gas cap removal.

Did he just call me seen isle?

Ya...I hear ya Street.The manual cautions about 'opening the filler cap'....I'm assuming this is what they mean....it will vent on it's own...my 07 used to sing all the time...I never worried about it...course...it didn't have a purge valve or anything...that's something new Kawi came up with...it's all good.I thought about 'removing' that evap canister and all...nah....it's working the way it's designed to....I don't want to mess with something that 'should' be there.Sa'll good.But I do think it does activate during certain times "on it's own' as the pressure builds or drops.The ECU and all isn't 'dead' because she's sitting there 'turned off'.