Carb bowl drain tubes

On my 82 kz750 h3 on the bottom of my carburetors the float bowls don't have any drain tubes hooked up to them, I've been reading around and it seems like I need some down there. I'm new to bikes so if anyone could let me know if I need me, where to get me from and how to hook them up I would appreciate it greatly, thanks!

May attach a hose to each overflow nipple protruding from bottoms of carbs' float bowls.

Gather the four hoses together and route them past the swing arm to discharge any escaping fuel underneath the bike.




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So the overflow drains are the ones at the very bottom of the carbs with the screws in them to drain them when needed correct? So I attach 4 hoses, 1 to each carb and just have them directed so they drip on the ground instead of the engine? And its normal for them bowls to gradually drip or what does that usually indicate. Cause the 2 left carb bowls drip here and there. Thanks

X_Saint wrote: So the overflow drains are the ones at the very bottom of the carbs with the screws in them to drain them when needed correct? So I attach 4 hoses, 1 to each carb and just have them directed so they drip on the ground instead of the engine? And its normal for them bowls to gradually drip or what does that usually indicate. Cause the 2 left carb bowls drip here and there. Thanks

As known, the drain screw (side of carb) is different from the overflow nipple (out bottom of float bowl).

Some carbs have an "overflow" circuit.
Other carbs don't have an "overflow" circuit.
An "overflow" circuit allows gasoline that exceeds a certain height level to escape .
Either type -- with or without an "overflow" circuit -- will have a "drain screw".
An "overflow" circuit is supposed to function when the drain screw is seated.
When the drain screw is loosened, all gasoline should flow out of the carb float bowl.

Yes, the drain hoses are attached to the carb overflow nipples, and are routed to exit underneath the bike whereby escaping gasoline may drip on the ground instead of the engine.

With a perfectly functioning float valve, a carb should not leak any gasoline through the overflow circuit.

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It may be that your overflow tubing is supposed to be routed to the airbox. Some 750-4s have a couple of grommets & Y-fittings that connect the tubing to the airbox. Check out the airbox & carburetor diagrams at Kawasaki.com for your model.

The rubber overflow hose clamp was a stock item on the 1976 KZ900-B1 LTD.

www.z1enterprises.com/ItemDetails.aspx?i...Strap&item=PM81-2182





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Also about the leak, you could disconnect the fuel line from the carbs & run it to a container to see if fuel drips while the petcock is set to ON or RES ---- Engine off - no fuel should flow (engine running - fuel should flow).
Fuel should flow when it is set to PRI.

A perfectly functioning float valve will maintain the correct fuel level inside the float bowl (which level isn't high enough to enter the overflow circuit), regardless of the petcock position.

Where a petcock is properly functioning, and set in a position that disallows fuel flow, the float valve has no fuel level to maintain.
This is the idea behind turning a manual petcock OFF, or leaving a vacuum petcock in ON or RES position, while the bike's engine isn't running (such as when parked or garaged).

Stopping gasoline flow through the petcock adds security against overflow leakage resulting from an imperfect float valve.
But, of course, does nothing toward correcting the imperfectly functioning float valve.

Nevertheless, it's the better practice when parking or garaging the bike to turn a manual petcock OFF, or leave a vacuum petcock in ON or RES position.
Ma-Kaw introduced the vacuum petcock so us ignorant forgetful reprobates wouldn't need to remember turning it off when the bike is parked or garaged.

But, if the manual petcock is leaking in the OFF position, or if the vacuum petcock is leaking in ON or RES position, gasoline will reach the float valve, and if the float valve is leaking for whatever reason, fuel level inside the float bowl will continue rising until escaping through the carb overflow circuit.

But what about a leaking float valve while the engine is running? --
Gasoline is passing through the petcock.
If the float valve is leaking badly enough, the fuel level rises to the overflow level, whereby excess incoming fuel gets past the imperfect float valve to escape through the overflow hose underneath the bike while riding.

What about carbs without an overflow circuit, or a clogged overflow circuit? --
Such as smoothbores, and some stock carbs.
If the float valve is leaking badly enough while riding, the fuel level may rise enough to enter the carb throat and get into the crankcase -- all while riding blissfully along, oblivious to the situation.

Recommendation -- Assure properly functioning float valves, and don't erroneously think that a good petcock in non-flow position while the bike's engine isn't running amounts to a cure-all for a leaking float valve.

My 2¢ :kiss:

Good Fortune!

martin_csr wrote: It may be that your overflow tubing is supposed to be routed to the airbox. Some 750-4s have a couple of grommets & Y-fittings that connect the tubing to the airbox. Check out the airbox & carburetor diagrams at Kawasaki.com for your model.

If not, the tubing is typically routed behind the engine & forward of the swing arm and away from the chain & mufflers. Some models don't have the neato tubing harness in Patton's photo.... my 81 650-CSR doesn't.

The dripping fuel could be from a defective petcock. Z1Enterprises.com sells a petcock rebuild kit. If the petcock seems to be in good shape & the rubber parts seem fine, a diaphragm repair kit may be sufficient... it's cheaper than the complete kit.

Thank you, I have been forever perplexed as to what those grommets are for. it would seem that the dirt or condensation would get in there and putting those hoses in floods the fool mixture.

donthaveakawman wrote: Thank you, I have been forever perplexed as to what those grommets are for. it would seem that the dirt or condensation would get in there and putting those hoses in floods the fool mixture.

I don't think fuel in the airbox will have much effect on the mixture. The fuel will simply evaporate & some (most?) of the fumes will get burned up by the engine. I guess if it floods enough, the excess fuel will then get dumped to the ground via the airbox drain tube.

from what I understand the increased vacuum inside the float bowls sinks the floats by pulling gas in there. I think I am going to skip it and get some pod racer filters.