Carburetor set-up...Does this look right?

I'm looking at the 2 tubes numbered "23" in the airbox diagram below and wondering if they would be vent tubes from the carbs.

No those are the Hoses that go from the Air Valve to the Valve cover. They are part of the fresh air system, to allow clean air into the exhaust for a more complete burning of exhaust gases.
Old cars had a Air Pump, or Smog Pump. Then they went to Pulse Air Injection, both before and after Catalytic Converters. Controlled by an Air Switching valve.
The Kawasaki Bikes just have a simple version of this, with a vacuum operated valve.

If you do remove the air system don't forget to seal the big airbox hole where hose #22 in the diagram would go.

I like tygon 1/4 i.d. fuel line. It stays flexible kinda like surgical hose so it doesn't kink. Comes in different translucent colors.

Motor Head wrote: No those are the Hoses that go from the Air Valve to the Valve cover. They are part of the fresh air system, to allow clean air into the exhaust for a more complete burning of exhaust gases.
Old cars had a Air Pump, or Smog Pump. Then they went to Pulse Air Injection, both before and after Catalytic Converters. Controlled by an Air Switching valve.
The Kawasaki Bikes just have a simple version of this, with a vacuum operated valve.

That's what I thought at first, but then when I looked at the valve cover diagram (see below) I didn't see that clean air junk. Ed

Try riding at highway speeds with the gas cap open. If the vent in the gas cap is plugged it will pull a vacuum in the tank and the fuel will stop flowing.

Been a while since I updated. The weather went too cold to work (no shop)

I drained the gas tank (mostly bc I used 87 Octane instead of 92 Octane...(Im an idiot) and didnt use stabilizer(again...idiot!) I took a small sample and noticed there were some solid particles in fuel. Since I decided to replace the fuel line anyway, I removed the filter and checked; clogged with red gunk.

Ive replaced the main fuel line and filter. At the same time I drained the two outside float bowls just to see what the gas looked like. The gas was mostly clear, but there were some solid particles in it.

Now, the bike wont start at all; choke or no choke. So Im thinking its time to rebuild the carbs.

Cause of problem? I think when I tried to clean out the gas tank, I didnt flush it out completely (oops!) and the rust clogged the carbs; making a bad situation worse.

And there are no hoses from the float bowls to the airbox or anywhere else. (I have noticed it missing) They appear to simply be a drain from the float bowl. (turn the drain screw; gas comes out of the bottom of the bowl)

mike_eubank wrote: And there are no hoses from the float bowls to the airbox or anywhere else. (I have noticed it missing) They appear to simply be a drain from the float bowl. (turn the drain screw; gas comes out of the bottom of the bowl)

My CV34 carbs do not have drain hoses either. I believe it was mentioned in another thread that some models also use the drain as a vent to atmosphere for the bowl.

Are we not supposed to use 87 octane gasoline? Hmm I've been using that for months thinking the compression is low enough. Perhaps I should try 89. I sure as heck ain't putting premium in my tank :pinch:

mike_eubank wrote: ...And there are no hoses from the float bowls...appear to simply be a drain from the float bowl. (turn the drain screw; gas comes out of the bottom of the bowl)

Some carbs are designed with the nipples at bottom of float bowls able to serve two different functions:

Drain screw tight = "overflow" nipples, allowing excessive incoming fuel to escape;

Drain screw loosened = "drain" nipples, allowing the float bowl to be manually drained of all fuel (also used in the clear-tube test).

Good Fortune!

Ive been told by some small engine mechanics I know that motorcycle engines run better with high octane fuel. Also, since I cant find ethanol-free gas anywhere, Ive been told that the higher octane helps burn out the ethanol a little better....dont suppose it could hurt, anyway.

Hopefully this weekend Ill be able to rebuild the carbs (should be fun.... ) I already got four rebuild kits. With any luck, Ill be able to ride the ol girl to the family christmas get-togethers.

I took the carbs off Saturday (not as hard as I thought, actually) I started to take them apart, but I noticed someone had already tried to rebuild the carbs before me...and seemingly damaged a few of the jets.

I started to feel a bit over my head, so I ran the carbs to the local Kawasaki place. A guy there was an expert in older bikes and told me the last thing I should do would be to dismantle the carb assembly; since most of the parts cant be found anymore.

I left them there to be cleaned via ultrasonic; which he claimed would be better than dipping.

All I know is that Im anxious as heck. This is my first bike and Ive only had one good days ride out of her. I just hope this cleaning solves the problem so I can get her back on the road.

i would think the idle air screws would be different on the center two carbs due to the fact that the outer two go to the clean air reed valves on top of the valve cover. i don't know if they are pulling more air into those or not, but the one that is blocked off and the one that is pulling off the petcock is not getting any air through it at all. on my 1980 kz750 h1 ltd-4 i am worried that the one pulling off the petcock is only one pull of vacuum per rpm as opposed to a car has a manifold for any vacuum issues that it would be dealing with.

my air-box has holes on the bottom with rubber fittings that have two holes on each so 4 holes total they appear to be for vacuum hoses but i don't know what they are for. i know they do not go to the overflow tubes on the float bowl and i don't want to leave them open for dirty air to get in. any hints or tips would be helpful. thanks

1980 kz750-4 ltd