Kawasaki Sportsbike Riders Club - Australia - Online Forum

At the risk of repeating any previous posts on this topic, can anyone tell me if the hissing sound coming from the tank filler cap is normal.

I went out for a ride (120km) and about an hour after I got home, I went to the garage to put the cover on the bike and could hear a hissing sound, like pressure slowly being released. I opened the fuel cap and got a big expulsion of air, but it stopped the hissing.

So, is this normal, or is there a blocked breather somewhere on the bike.

Look forward to any thoughts

My ZZR600 did the same thing, and I was under the impression this is normal as the cap is vented to allow this to occur.

HTH, Mick

normal, generally does it during hot days in my experience, I generally just open the cap and then close and there's no more hissing
TC

ruuuuuuuuuun! she's gunna blow!!!

Its a good sign slaps, its whan you dont hear that sound you have to worry

Yep asthe other have said, it's nothing to worry about and is a "Feature" of the bike. It is termed a "vented Fuel Cap". It's purpose is to equalise the pressure inside and outside the tank when temps vary. It also stops hydraulic lock of the fuel. If no vent, then the fuel would struggle to be sucked out of a vacuum.


As I mentioned in my welcome post to you, I have one of these and have pulled it apart and put it back together a couple of times. Not much a I can't do on one of these. So if you have any issues, just PM me.

Strika wrote:Yep asthe other have said, it's nothing to worry about and is a "Feature" of the bike. It is termed a "vented Fuel Cap". It's purpose is to equalise the pressure inside and outside the tank when temps vary. It also stops hydraulic lock of the fuel. If no vent, then the fuel would struggle to be sucked out of a vacuum.


As I mentioned in my welcome post to you, I have one of these and have pulled it apart and put it back together a couple of times. Not much a I can't do on one of these. So if you have any issues, just PM me.

Thanks for the interest & feedback on my "perceived" problem. I really appreciate that people actaully care. It's good to see that the camaraderie has not disappeared after my time away from bikes.

slaps999 wrote:

Strika wrote:Yep asthe other have said, it's nothing to worry about and is a "Feature" of the bike. It is termed a "vented Fuel Cap". It's purpose is to equalise the pressure inside and outside the tank when temps vary. It also stops hydraulic lock of the fuel. If no vent, then the fuel would struggle to be sucked out of a vacuum.


As I mentioned in my welcome post to you, I have one of these and have pulled it apart and put it back together a couple of times. Not much a I can't do on one of these. So if you have any issues, just PM me.

Thanks for the interest & feedback on my "perceived" problem. I really appreciate that people actaully care. It's good to see that the camaraderie has not disappeared after my time away from bikes.

Unfortunately it's not like it was 20 or more years ago. Many of the newer breed have little if any of that old attitude to other riders. In the past, I never witnessed a rider not stopping for another rider who may have broken down or had a mishap or puncture. These days it is less likely to occur. In here however, there appears to be more of a respresentation of that comeraderie of the past even with some of our later model members!!

However, to balance that out, there is a fair bit of pisstaking too. So don't get ancy if someone comes back with a smartarse reply! Matter of fact, if you're like the rest of us, you'll encourage and maybe even participate in it.

The fact that you own and ride A ZRX and not just any ZRX, but one of the more special "S" models as have I, indicates that you are an intelligent man, so I am sure you will work out what's what and who's who in the Zoo fairly quickly!

Same happened to me i though sumfin was wrong but its a feature,note to self Dont ride long distances with a tank bag cos if u block the vent it will starve the bike and u will be scratching your head like i was for hours,just am little note,Cheers Clanga

I have seen two diferent Z1000's die in the ass from blocked caps.... stop wait a bit starts up fine... ride till it stops again scratch head... & of course the cap is the last place you would look for a problem
Note thats fuel injected Zed's

We had this issue on a mate R6's at PI earlier this year, we had the bike in a million parts in the living room where we were staying thinking it was the fuel pump, in the end to find it was a loose battery terminal....

Strika wrote:..... In the past, I never witnessed a rider not stopping for another rider who may have broken down or had a mishap or puncture. These days it is less likely to occur.....

I still pull over to check on bikes when I see them stopped at the side of the road - have to say though, that seems to happen a lot less these days than it used to ! Must be something to do with all the Honda 4's that are no longer seen on the road....

I am going to suggest removing the fuel cap and give it a clean out. I had similar issues on the Z750 a while back. Cleaned the cap, stopped the noise

I first noticed at two in the morning laying bed - I thought it was a possum outside before I realized it was my bike. The guys in the shop told me it was all good; just equalizing presseure.

It does get annoying though for me as it does allot