Tank Venting KZ1000 LTD 82

Hi all, first time poster.

So I pick up my 82 KZ1000 LTD and discover that the PO has installed an auxiliary fuel shutoff.
Anyway, my wife is not delighted with my new friend, and less so with gas on the garage floor. Yeah, it happened and soon.

OK, so I did my reading and study, of many wise folks here and elsewhere. Ends up I decide to put in carb kits, back to stock jets (J model 127.5 main with my Vance header, stock airbox, and back to stock needle. He had done a Dynojet kit with pods, and I didn't like the behavior in cross winds etc.

So I cleaned and installed. Comes spring, set the mixture screws, and sync the carbs. Running good.

This morning, I have gas on the floor, in spite of new float valves, setting float height to spec, and fuel levels all check at/below carb mating line.

Pulled apart the gas cap...there's a heavy (I think) coat of grease. In around out and under. I washed it out good, and applied a verrry light coat of grease.

How about it guys? It happens after a ride. Engine heat turns to tank heat...and no venting. The petcock even kitted is still a major leaker (heard that before)...and so is a few pounds of vapor pressure enough to open my float needles?

The fuel levels checked out again tonight.

I have a 12v fuel shutoff coming soon, that should give some isolation but I am still really buggered by this one.

Thanks,
Chuck

Is the gasoline that's on the floor coming from overflow hoses?

Imo the gas cap should be clean and free from any grease whatever.
Perhaps the grease is obstructing the vent.

A properly functioning vent disallows pressure build-up inside the tank.

Good Fortune!

Yes, a clogged fuel tank vent can cause fuel to leak out of the carbs when the bike is sitting. The innards of the gas cap need to be clean and dry - no grease of gunk. Here's a recent example of the same symptoms cured by cleaning the vent:

kzrider.com/forum/3-carburetor/586852-leaky-petcock#586853

Thanks Patton and 650ED for getting back to me. Here's one I am still confused about: overflow hoses. The hose connections I see to the carb bank, that is, with hose barb connections, are:
a. Float bowl drain valves x 4
b. Vacuum line connections x 4 (cyl 1,4 to air valve, cyl 3 plugged, cyl 2 vacuum petcock)
c. Fuel line connection between #2 and #3 carb.

I'm not understanding where the overflow connections are/were, and why I am getting drainage up into the carb body. They all got a four hour soak in the good stuff, and were aggressively blown out with compressed air. I'd gladly dig into these BS34's again to get that overflow thing right, rather than be pressed into another oil change due to gas infiltration.

There appears to be a tiny vent of sorts near the border of the bowl gasket in the rear, is that relevant?

Again, THANKS for your help!

Chuck

I have VM carbs, so I can't me much help on the BS type, but the link below has some BS34 info that might be helpful. Ed

www.wgcarbs.com//index.php?option=com_co...sk=view&id=Itemid=86

WOW WiredGorge has a cool site! Here's the snip I was looking for:

"BS series carburetors do not have overflow circuits."

OK. So all there is is bowl venting and that does appear to happen at the intake venturi as he says. Bottom line the vapor pressure issue simply must be solved.

Great education, folks, and THANKS. Wish I would have beeped in sooner!

Regards,
Chuck

Sherman47 wrote: ...hose connections I see to the carb bank, that is, with hose barb connections, are:
a. Float bowl drain valves x 4....

Is there a hose attached to a nipple on the bottom of each float bowl?

If so, is the gasoline that's on the floor coming from one or more of such hoses?

If not, where is the gasoline escaping from the carbs?

An experiment -- loosen (don't remove) a drain screw to see whether or not the loosening allows gasoline to exit from a hose onto the floor.

Some carb designs provide an overflow function when the drain screw is in its normal tightened position, but convert the overflow function into a drain function when the drain screw is loosened.

Am thinking (but not positive) that a carb without an overflow circuit doesn't have a hose attached to a nipple from the bottom of float bowl.

Good Fortune!