TOPIC:

That breather definitely shows an arrow on the housing indicating flow and you can see that indication in the parts diagram.

Just went out into the garage and rummaged through the parts boxes and found the breather probably the last one in exsistence




It's hollow, nothing inside it and


It has a hole on the top side of the body. Another Nuclear Mystery. Thoughts??

Kawboy wrote:

stocktoy wrote: Looking at the images of the aftermarket and the OEM fuel caps I would think that you'd get fuel splash because there's nothing there to draw the fuel down the overflow tube correct me if I'm mistaken

You're losing me here Stocktoy. That hole in the top of the tank is not part of an overflow system. And when all of thr right parts as designed by kawasaki are in place, fuel nor air can go "down" that hole and out to the ground because the fuel tank breather is a one way valve only allowing air into the tank.

The fuel tank breather is the item below item #2

My thinking was that if the OEM cap had a nipple on it that went into the vent tube thereby letting any expanded fuel vapor/raw gas flow to the ground that if the nipple isn't there and the cap is vented as you feel the non OEM one is then it vents under the cap cover (under the cap cover - my thoughts) and would allow the vapor/raw fuel to expel on to the top of the tank (on my 79's I don't have that check valve in the hose - just the rubber hose)

The thought of raw gas coming out of the top of the fuel tank and possibly running down and soaking the family jewels (not that they're jewels anymore, more like dead rocks on the road) scares me. Reminds me of an instance when I sat down on a 5 gallon polyethylene fuel tank that was full of gasoline, and the vent cap was open. 20 seconds later I realized the the vent hole squirted the ol' crotch area. I pulled off the fastest strip tease without music and ran for a garden hose. I'm much more in favor of getting that venting/overpressure relief system with the drain tube working properly.

Thanks for this Kawboy- a good reminder actually. I've been riding my bike for years without that hose attached, never filling the tank right to the top ( the 27 litres gives lots of range ) , but it was another "thing " to have to remove to get the tank off -which was quite regularly.

Anyway - for the real purist out there , that part is still available - but too rich for me. I'll run the vent hose off the tank , combining it with the other two hoses under the bike-battery and radiator bottle.
Check this place out.
It's not so much the cost of the part, but the 5 times price increase for freight !


www.cmsnl.com/kawasaki-kz1300a2-1980-usa...fuel-tank_140691004/

The "System" that's being discussed does both. It's a vent so the tank can remain at atmosphere as the fuel level changes and it's also a drain for a fuel overflow condition. The hole in the breather helps avoid a vapor lock in the entire length of the vent system, allowing vapor and liquid to be discharged freely. Think of that little hole working in the same way as a plumbing vent pipe that for a good reason must be within a required distance from the sink-drain.

scotch wrote: Just looked at the drawing showing the in-line device on the tank vent hose. If my bike ('80) ever had this fuel-filter "look-a-like" device I can't remember it, but have not had anything like this on my vent line for as long as I can remember.
I don't recall where I read this, but I do recall this topic somewhere (could have been another site and another bike) and My recollection is that it was to prevent a "lock" in the hose if road-water got up into the draining end of the hose which was theorized to cause a vacuum in the tank which we know will cause fuel starvation. So I'm suggesting it is not a valve assembly of any type. It simply provides a volumous area for interrupting the "sucking-in" of water. AND Yes I would have to agree - The fuel tank would have to be emptying fuel at a pretty good rate to pull water up into the vent-hose. Think about it: The vent hose must let air in as fuel is depleted and like wise must let air out in the case of expansion.
If there is a check-valve component in the device it would have to have a VERY lightly sprung mechanism to allow for venting either way. And that sounds like a problem area if dirty
Anyone willing to cut one open to see how it does work?

Yes I remember reading that somewhere too, although I seem to remember reading that there had been a couple of cases where that vent line had blocked & caused the bike to stall just as the owner was attempting to pull away causing them to drop the bike, which is why they introduced that part after launch.
When I fitted the flush-fitting aircraft-type tank fuel cap to my 13 I moved the breather to the front top of the tank just in front of the filler, an anti-spill device is screwed into the tank & then the flexible breather line goes forward (as on Motocross bikes) then goes to the original exit place with the battery breather via that plastic cannister device you describe. Works OK