Author Topic: Air cleaner housing hoses  (Read 2525 times)

Offline AtLarge

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Air cleaner housing hoses
« on: June 29, 2023, 03:13:54 PM »
Found a hose disconnected on my brick.  Tried to look it up on the fiche and it is not shown.  The nipple above the air cleaner isn't shown in the drawing either so, I drew a line where it would be approximately?


Snooping around on the site I couldn't find anyone with a similar problem but, I did find a picture from another member that does show it in green here:


Since the bike it running well with it disconnected I am assuming it's not critical?  Probably emissions but, what is it connected to behind the throttle bodies?  I want to reattach it but, of course it's not easy to reach on that side.

Could I just cap it off at both ends and remove the hose completely OR I have to take it out, remove the OE pinch hose clamp, and  reattach with a screw style clamp (which will not be easy to get to).

Any suggestions?
  • IA
  • 1994 K1100RS
1973 Honda CL70-K3, 1975 Kawasaki 350 F9-C, 1994 BMW K1100RS, 2023 Honda CRF300L Rally ABS

Offline Scott_

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Re: Air cleaner housing hoses
« Reply #1 on: June 29, 2023, 05:54:34 PM »
There should be 2 small lines that connect to the air box.
1 line connects to the bottom of the cyclonic oil separator that is an integral part of the top lid of the air cleaner, and is supposed to drain the separated oil back to the crankcase. #9 in 1st image.
The other line is from the vent at the back of the crankcase #10 in 2nd image.

Both are considered part of "emissions"


  • My Garage
1995 K1100LT 0302044
2017 FLHTK Ultra Limited
1997 K1100LT 0302488 (R.I.P.)
1997 R1100RT ZC62149(sold)
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Offline Laitch

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Re: Air cleaner housing hoses
« Reply #2 on: June 29, 2023, 06:21:48 PM »
One port is for air return; one is for oil return. They're illustrated in the K1100 manual downloadable from this site, but you need x-ray imagination and transpositional skill to understand their set up unless you visit eBay. They're part of the cyclonic oil separator system—as Scott explained while I was dawdling over sentence construction—an emission control device. I'm just a lowly K75 owner but the Maven of K-landia or the Mighty Gryphon might explain it all to you, if either feel so moved.  :laughing4-giggles:
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Offline Laitch

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Re: Air cleaner housing hoses
« Reply #3 on: June 29, 2023, 07:10:49 PM »
Well, now I understand, more or less. Don't let that chunky device on the table confound you. The small circular device illustrated in the prior post is designed around the same concept.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline AtLarge

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Re: Air cleaner housing hoses
« Reply #4 on: June 29, 2023, 07:28:33 PM »
Ah… got it now. I have an idea to reattach it without too much disassembly. Will take a shot in the morning when it’s cooler. Thanks Guys!  icon_cheers
  • IA
  • 1994 K1100RS
1973 Honda CL70-K3, 1975 Kawasaki 350 F9-C, 1994 BMW K1100RS, 2023 Honda CRF300L Rally ABS

Offline Laitch

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Re: Air cleaner housing hoses
« Reply #5 on: June 29, 2023, 09:53:28 PM »
Will take a shot in the morning when it’s cooler. Thanks Guys!  icon_cheers
Before you start, you should realize that the separation function of that separator might be compromised by age. It's function now might be strictly to stabilize crankcase pressure. Whether it can continue its full emission function depends on its guts. Take a look at this post.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline AtLarge

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Re: Air cleaner housing hoses
« Reply #6 on: June 29, 2023, 11:51:04 PM »
Actually, I stumbled on to that one earlier but, breezed over it to be a "can I run Pods" kinda post.  Now that I've gone back and actually read it my understanding is clearer. I don't want to get into the airbox to examine the Cyclotronic Weathermaker but, I don't really want to leave the port open to the elements either.  Thanks for pointing this out.  My bike is a a 94, rode hard, put up wet kind of bike so, I wouldn't be surprised if the canister is in the same condition inside as Saints.  Gonna have to think this through first before proceeding.  :idunno:
  • IA
  • 1994 K1100RS
1973 Honda CL70-K3, 1975 Kawasaki 350 F9-C, 1994 BMW K1100RS, 2023 Honda CRF300L Rally ABS

Offline Scott_

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Re: Air cleaner housing hoses
« Reply #7 on: June 30, 2023, 07:13:13 AM »
You could plug all 3 ports and be ok. I've done it on mine. The location in the top of the air box is more to do with gravity(and hiding it out of sight) for the oil to return to the engine than anything else. It isn't open to the inside of the air box.
  • My Garage
1995 K1100LT 0302044
2017 FLHTK Ultra Limited
1997 K1100LT 0302488 (R.I.P.)
1997 R1100RT ZC62149(sold)
"One who does not ask questions is ashamed to learn" Danish proverb

Offline AtLarge

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Re: Air cleaner housing hoses
« Reply #8 on: June 30, 2023, 07:48:52 AM »
If I just use a rubber cap behind the throttle body to seal the intake there will it effect it running?  I don’t want more adjustments. I want to ride.
  • IA
  • 1994 K1100RS
1973 Honda CL70-K3, 1975 Kawasaki 350 F9-C, 1994 BMW K1100RS, 2023 Honda CRF300L Rally ABS

Offline Scott_

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Re: Air cleaner housing hoses
« Reply #9 on: June 30, 2023, 05:23:27 PM »
Let me put it this way if it will help.

If you connected all the hoses/lines and have an air-tight block, it would be the same as capping that line behind the intake.
I took that intake line and connected it to vents on both ends of the block. At least that way the intake will suck up any blow-by from out of the crankcase, and keep it in a negative relative to atmosphere.
Yes it may suck some oil vapor and burn it, that's where the separator would have filtered it out and drained it back to the engine instead of burning it. Other than that the vac system would be the same.
  • My Garage
1995 K1100LT 0302044
2017 FLHTK Ultra Limited
1997 K1100LT 0302488 (R.I.P.)
1997 R1100RT ZC62149(sold)
"One who does not ask questions is ashamed to learn" Danish proverb

Offline AtLarge

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Re: Air cleaner housing hoses
« Reply #10 on: June 30, 2023, 09:40:12 PM »
Good enough then. I’m plugging both. Thanks!  112350
  • IA
  • 1994 K1100RS
1973 Honda CL70-K3, 1975 Kawasaki 350 F9-C, 1994 BMW K1100RS, 2023 Honda CRF300L Rally ABS

Offline Scott_

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Re: Air cleaner housing hoses
« Reply #11 on: July 01, 2023, 12:01:47 PM »
Can I recommend that you at least connect 1 to the block. The last thing you want to do is have positive pressure in the crankcase and risk blowing out your oil sight glass.
Just a friendly tip.
  • My Garage
1995 K1100LT 0302044
2017 FLHTK Ultra Limited
1997 K1100LT 0302488 (R.I.P.)
1997 R1100RT ZC62149(sold)
"One who does not ask questions is ashamed to learn" Danish proverb

Offline AtLarge

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Re: Air cleaner housing hoses
« Reply #12 on: July 01, 2023, 01:50:28 PM »
I got it done this morning but, no time for a shake down ride now.  Rain moved in and festivities this afternoon.  Definitely tomorrow though.  Did have a couple surprises. The nipple behind the #2 throttle body is a plastic bushing! Found that out after I pushed the rubber cap on and realized it was a little long.  Pulled it off to shorten it and it came with the bushing.   177381  To get an automotive grade rubber cap had to buy the whole Dorman set of course.  I can add the extras to my collection in hopes of using the rest someday. I was just going to plug the hose but didn't make much sense to have it flopping around so, just took it off and capped the nipple on the air box too.  Will clean it up and save for the future too.

As to your comment, I still have the second hose connected and that's the one that goes to the block I believe.  When I took it off to get it out of the way I got a little water / oil out of it so, it's doing something and that's why I left it on. Removed a couple leaves and scrapped some crud here and there and I think I'm good to go now.  I will have to eyeball that plug behind the throttle body once in awhile and make sure it stays in and there's really nothing to secure it.  Since it's just a pressed in plastic bushing it could eject.  Fortunately, I think it sucks there instead of blow so, should stay in place.   :laughing1:

I did the rear drive and tranny oil change too and will commence to Motobrickin' soon.   44271
  • IA
  • 1994 K1100RS
1973 Honda CL70-K3, 1975 Kawasaki 350 F9-C, 1994 BMW K1100RS, 2023 Honda CRF300L Rally ABS

Offline Scott_

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Re: Air cleaner housing hoses
« Reply #13 on: July 01, 2023, 07:23:29 PM »
I hear you about the weather... I didn't get any riding in today either because of the rain.
So me n the mrs visited grandkids and did some shopping instead.
  • My Garage
1995 K1100LT 0302044
2017 FLHTK Ultra Limited
1997 K1100LT 0302488 (R.I.P.)
1997 R1100RT ZC62149(sold)
"One who does not ask questions is ashamed to learn" Danish proverb

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