Author Topic: Mysterious rubber piece found in bottom of air box, what is this?  (Read 2661 times)

0 Members and 1 Guest are viewing this topic.

Offline drj434343

  • Enthusiast
  • **
  • Posts: 103
I found a mysterious rubber piece loose in the bottom of my air box after removing my air filter.  This is a very original 71' CB500 running an OEM style filter.

See the attached picture.  I looked all over the air box area looking for an obvious home, but couldn't find a place where this was supposed to go.  The filter itself also doesn't seem to need this piece.  Any ideas?
1971 CB500 K0
1974 CT90 K5

Online RAFster122s

  • I feel like a really really
  • Really Old Timer ...
  • *******
  • Posts: 12,356
  • SOHC4 member # 2605
Re: Mysterious rubber piece found in bottom of air box, what is this?
« Reply #1 on: July 23, 2013, 09:58:45 AM »
Send it to me...

It goes in front of the box cover and seals the cover/tray to the air box plenum. This allows the air to be coming from the oval screened opening, a metered or regulated intake.

Could you measure it or put it on some graph paper with a ruler beside it so I could replicate it in plastic or other material?

Thanks!

David
David- back in the desert SW!

Offline drj434343

  • Enthusiast
  • **
  • Posts: 103
Re: Mysterious rubber piece found in bottom of air box, what is this?
« Reply #2 on: July 23, 2013, 10:14:31 AM »
OK, so it does belong somewhere.

I will give it a second look per your instructions when I get home.  I will also take additional pictures to give scale for reproduction, although it isn't the easiest piece to express with 2D pictures.  It would be the perfect candidate for reproduction with 3D printing (after a CAD model was developed), but I digress.
1971 CB500 K0
1974 CT90 K5

Offline lone*X

  • Expert
  • ****
  • Posts: 1,126
Re: Mysterious rubber piece found in bottom of air box, what is this?
« Reply #3 on: July 23, 2013, 10:49:22 AM »
When looking for where something goes, no better place than looking a the parts fiche for you model.   Draw a line straight down from the seal in the fiche to the front edge of the airbox.  The seal is groved on one side to sit on the front edge of the airbox.

« Last Edit: July 23, 2013, 10:50:56 AM by lone*X »
Lone*X  ( Don )

75 CB550K1  
VTX1800C for two up cruisin.
Several others have come and gone but whose keeping track.
52 years on two wheels and counting.....
"The best safety feature of any motorcycle is the one God put between your ears.  It's also the least utilized"

Offline SohRon

  • She laughs 'til she cries when they call me an
  • Expert
  • ****
  • Posts: 946
Re: Mysterious rubber piece found in bottom of air box, what is this?
« Reply #4 on: July 23, 2013, 05:00:33 PM »
Here's what it looks like in place. Its main purpose is to deflect moisture (rain, etc) from entering the system from the front of the bike. It seals the cover to the filter box as well; you'll have an air leak without it installed.

« Last Edit: July 23, 2013, 05:05:31 PM by SohRon »
"He slipped back down the alley with some roly-poly little bat-faced girl..."

Assembling my '74 CB550: http://forums.sohc4.net/index.php?topic=86697.0
Assembly of the Right-hand Switch (a rebuilder's guide):  http://forums.sohc4.net/index.php?topic=80532.0
Installing stock 4X4 exhaust: CB500-CB550 K: http://forums.sohc4.net/index.php?topic=82323.0
CB550 Assembly Manual: http://forums.sohc4.net/index.php/topic,151576.0.html

Offline Bailgang

  • Scott
  • Old Timer
  • ******
  • Posts: 2,705
  • Indiana
Re: Mysterious rubber piece found in bottom of air box, what is this?
« Reply #5 on: July 23, 2013, 05:22:15 PM »
Excellent info, after seeing this I looked up a parts fiche for my 75 550 and sure enough mine is supposed to have that as well and I never knew it until now. Only problem now is finding a replacement because it seems to be a discontinued part.
Scott


71 cb350 twin
77 cb750 F2
83 gl1100 Interstate

Offline Kenzo1979

  • Hot Shot
  • ***
  • Posts: 544
Re: Mysterious rubber piece found in bottom of air box, what is this?
« Reply #6 on: July 23, 2013, 06:42:57 PM »
Wow!  I think this part must be the first thing to get lost.  I have a 500 and 3 550's sitting in my garage as well as several others I worked on and have never seen this damn thing.  HAHAHA!
--Kenzo
** 71 CB500, 74 CB550, 76 CB400F, 77 CJ360t **

Offline reddyvv

  • Hot Shot
  • ***
  • Posts: 252
Re: Mysterious rubber piece found in bottom of air box, what is this?
« Reply #7 on: July 23, 2013, 07:32:14 PM »
drj434343,

Don't listen to all these comments. It really is a worthless, problem causing piece of rubber that was used to protect the air cleaner when shipping the bikes. If you send it to me I promise to dispose of it properly so it never harms another bike again  ;)

Online RAFster122s

  • I feel like a really really
  • Really Old Timer ...
  • *******
  • Posts: 12,356
  • SOHC4 member # 2605
Re: Mysterious rubber piece found in bottom of air box, what is this?
« Reply #8 on: July 23, 2013, 07:37:27 PM »
drj434343,

Don't listen to all these comments. It really is a worthless, problem causing piece of rubber that was used to protect the air cleaner when shipping the bikes. If you send it to me I promise to dispose of it properly so it never harms another bike again  ;)

Get in line, I have first claim on it if he's getting rid of it...
David- back in the desert SW!

Online RAFster122s

  • I feel like a really really
  • Really Old Timer ...
  • *******
  • Posts: 12,356
  • SOHC4 member # 2605
Re: Mysterious rubber piece found in bottom of air box, what is this?
« Reply #9 on: July 23, 2013, 07:39:31 PM »
We need to get a good one to Claus Studios to make replacements as several owners need these, or could use them. Nice thing is Claus gives them a free one if I recall correctly.
David- back in the desert SW!

Offline reddyvv

  • Hot Shot
  • ***
  • Posts: 252
Re: Mysterious rubber piece found in bottom of air box, what is this?
« Reply #10 on: July 23, 2013, 08:10:15 PM »
drj434343,

Don't listen to all these comments. It really is a worthless, problem causing piece of rubber that was used to protect the air cleaner when shipping the bikes. If you send it to me I promise to dispose of it properly so it never harms another bike again  ;)

Get in line, I have first claim on it if he's getting rid of it...

You think it's useful. But it is just trouble and I want to chop it up into little bits and dispose of it.  ;D

Offline reddyvv

  • Hot Shot
  • ***
  • Posts: 252
Re: Mysterious rubber piece found in bottom of air box, what is this?
« Reply #11 on: July 23, 2013, 08:15:29 PM »
We need to get a good one to Claus Studios to make replacements as several owners need these, or could use them. Nice thing is Claus gives them a free one if I recall correctly.

Good idea. I wish someone would make the airbox drain tube too. I think SohRon bought the last one on the planet - in addition to a new set of exhausts, but that's another story.   (no icon for jealous  ???)
« Last Edit: July 23, 2013, 08:18:25 PM by reddyvv »

Offline drj434343

  • Enthusiast
  • **
  • Posts: 103
Re: Mysterious rubber piece found in bottom of air box, what is this?
« Reply #12 on: July 24, 2013, 04:34:38 PM »
Don't know why it wasn't obvious where it went before...  I opened the seat back up and saw where it needed to go.  The first time around I had the filter out, and the big empty air box suggested a lot more placement options.

I attached a few pictures with scale.  This looks like a difficult part to reproduce.  I can also see why these things got lost immediately.

1971 CB500 K0
1974 CT90 K5

Online RAFster122s

  • I feel like a really really
  • Really Old Timer ...
  • *******
  • Posts: 12,356
  • SOHC4 member # 2605
Re: Mysterious rubber piece found in bottom of air box, what is this?
« Reply #13 on: July 24, 2013, 04:41:28 PM »
DRJ/aka #1,
Thanks for the pictures. Appreciate it.
David
David- back in the desert SW!

Offline drj434343

  • Enthusiast
  • **
  • Posts: 103
Re: Mysterious rubber piece found in bottom of air box, what is this?
« Reply #14 on: July 24, 2013, 04:55:04 PM »
I should add, I can, at some point, create a 3D CAD model of this, but my current schedule won't allow it in the near term.  However, if someone else here has the skills and inclination in the short term, I would be happy to lend the part for such an effort, especially if someone could use the file to reproduce these things.

Not sure sure what the widespread interest would be.  It would be hard to make the development costs back reproducing a part as small and cheap as this.
1971 CB500 K0
1974 CT90 K5