Gas tank hissing

[nick0484]

I just recently had my Carbs cleaned on my 88 kat 600. I also had the plugs changed, new gasket because i was leaking fuel into a cylinder from one of the carbs, and a fresh oil change. The bike does run great, but i have noticed after i get done riding the gas cap hisses. If i unlock the cap and open it, it stops, but as soon as i relock and close the gas tank lid, the hissing continues. It sounds as if it is coming from the key hole...??? Has anyone had this happen before. It is not very noticeable, but it can be heard. Any help would benefit me. Thanks
Nick

[Black_peter]

It's mad 'cause you stopped riding it!


It's the tank venting.. The vent is in the cap.

[katman05]

It's normal, don't sweat it. http://katriders.com/vb/showthread.p...t=hissing+tank

[HemiKat]

We all need to relieve a little pressure now and then...

[Ghall001]

my vilcan did that and I removed the gas cap and theres a little hole under there for a vent, I just drilled it out a little bigger and it stopped

[nick0484]

I dont remember this ever happening last year when i rode the bike. Could it be doing this now that the carbs are all sealed up and not leaking fuel anymore? As I stated before, the guy that cleaned them said there was a ton of fuel in the airbox and he replaced the gasket and everything else.

[axelpkt]

I noticed my Kat doing this the other day, I didn't know what was going on. I thought that rubber seal on the cap was going bad, guess not.

[nick0484]

I noticed my Kat doing this the other day, I didn't know what was going on. I thought that rubber seal on the cap was going bad, guess not.

That's what I was thinking was wrong with mine also, but I guess I found out otherwise.

[GregS]

Your vent hose may be blocked off or clogged. On newer California models the vent is directed to a carbon filled canister. On older bikes the vent is just to atmosphere.
The gas cap is set up to vent excessive pressure but often this is a back up pressure relief to the hose. You don't really want constant pressure in your tank when not running since it can overcome the float valves sealing abilities and cause flooding.