dirty valve diaphragm?

Hi there!
I'm cleaning my carbs on my kz1100 A2 and the bottom of the valve diaphragms on carbs #2 & #3 look pretty dirty. Oil? #1 and #2 look fine.

What would this indicate? Ive definitely seen some smoke on initial start over the past several months and need to replace the washers on all 4 exhaust. Maybe oil is dripping in somehow in there? #2 and#3 sounds like it could be electrical but the dirt/oil doesn't make sense to me.
I'm attaching a pic of cab #1 and #2 side-by side.

Thanks for any help!

That's the intake side of the carbs. What kind of air filter do you have and is it clean?

BTW, please click "insert all" relative to your photos before posting. That way the photos will show up in high resolution instead of tiny thumbnails.

The Air filter looks relatively clean. I replaced it a couple of years back when it was very dirty. I'm not sure what kind it is. but the Airbox defiantly looks very dirty and the hose that comes from the air switch valve (?) to the airbox is dripping with oil...

I know that the airbox is supposed to get rid of excess oil, but this seems like a big mess... Does this look right?

I can figure out basic mechanics, but I'm still learning about a lot of this and appreciate your help in understanding

That tube is your crankcase breather and that amount of oil is normal. I've seen WAY worse.

Looks to me like the hose from the PAIR system. If so, it should be dry. The crankcase breather should be a smaller, shorter hose from the oil separator on top of the transmission case to the bottom of the air filter box. It will be oily inside.

92059D and 92059C in the diagram.

www.partzilla.com/catalog/kawasaki/motor...z1100-a2/air-cleaner

Correct, Texas: the part # 92059D is the hose I am referring to. It's just called "tube" on the partzilla diagram. That's why I wasn't sure what it was called or what it is actually for. Seems like it may be the vacuum for the PAIR system. That tube is attached to the top (not the bottom) of the airbox.

Part #92059C, which drains oil from the airbox, as far as I know. It's called "air filter bleed" on the diagram and it comes out the bottom of the airbox.

That being said, should it have oil on it? If not, why would there be oil?

Tube D takes filtered air from the air box to the exhaust ports via the reed valves on top of the cam cover. No oil is involved. The vacuum for the valve comes from two of the carburetors via the small diameter hoses in the diagram.

The crankcase vent tube (C) will be a little oily. Blow by from the rings would pressurize the crankcase and eventually blow out seals if there was no vent. The whirling crankshaft, rods, and transmission gears create a fine oil mist inside the crankcase, a bit of which exits with the blow by, and gets sucked into the air filter box. There will be an oily film inside the tube and in the bottom of the air box. The box should be wiped out periodically, like whenever the filter is changed or checked.

The only way I can imagine for that end of tube D to have oil in it is there is a pretty heavy oil mist coming out of tube C and for some reason the engine is not sucking it all up, so some is getting to D.

Is your air filter a dry paper element type, or is it like a K&N that needs periodic (over) oiling?

Thanks for the explanation! Every time I check into an issue, I'm learning a lot more about the bike, so this was very useful.
The oily mist would have to be pretty extreme I guess if it were to get up to that D tube. They are pretty far apart. Both of them are in the front compartment of the airbox, which does not contain the air filter.

I have the type of filter that needs Oiling. I pulled it out the other day and cleaned it and re-oiled it, but it wasn't all that dirty. I have had a lot of oil leak problems over the past few years and usually have to carry around oil to refill ... often, so I supposed there may have been times when I put a bit too much in and maybe that put some extra into the airbox? ( I have since done an engine rebuild, which stopped leaking from the top gasket. More recently I replaced the o-ring on the chain tensioner, because the was oil leaking from there still after the rebuild).

I'm wondering about this construction, though. Why allow: "oily mist" into the airbox in front of (not behind) the air filter? I guess that is how oil may be getting into my carb intakes. It's just strange that #1 &4 are super clean and #3&4 are dirty.