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Breather bypass

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Old Jan 11, 2023 | 04:01 PM
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Default Breather bypass

Has anyone done a breather bypass on a 107 M8 using and leaving the stock air cleaner in place?
 
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Old Jan 11, 2023 | 10:06 PM
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Originally Posted by Ken45
Has anyone done a breather bypass on a 107 M8 using and leaving the stock air cleaner in place?
I've seen a few who have done it... try searching here and you should find a thread or two about that very mod...
 
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Old Jan 12, 2023 | 08:05 AM
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Not on a M8, but I believe this is a similar breather, just for an idea....



 

Last edited by Ssitruc; Jan 12, 2023 at 08:13 AM.
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Old Jan 12, 2023 | 09:43 AM
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Here's a thread that may have some ideas for you:

Finally did my breather bypass (pics included) - Harley Davidson Forums (hdforums.com)

And the post I just made to that thread addressing your exact question:

I haven't been through the 68 pages of this thread to see all the variations, but if you're running the OEM air cleaner in a late model touring bike air cleaner housing, you can pull the breather tube connection out of the tube in the back of the air cleaner, attach a rubber hose to it, drill a hole in the back of the cleaner housing, and run the hose out and down.

To clarify, each breather bolt has a tube connected to it. The tubes are joined together by a T-fitting, with the third prong of the fitting going into a crooked little tube that goes into a hole in the air cleaner itself (to route the goo to the intake). You pull the third prong of the fitting out of the crooked little tube and attach that to your new hose to be routed out and down. You'll want to remove the crooked little tube from the air filter since it will now allow unfiltered air to enter, and plug the hole (or just plug the tube itself). This costs no more than the cost of the hose, plus an old screw or plug of some kind (make sure it's something that won't get sucked in!).

Writing this at work, so no pics handy, but I can take some if it's not clear.

Links below for the hose I used (just for example - you don't need that much), and some silicone plugs (again, you don't need this many, and you could just put a screw in the hole for free, probably).

Amazon.com: NEW DAFU 1/4 Inch 6mm ID NBR Nylon Braided Fuel Line Set,10 Feet+20 Pcs 2/5 Inch ID Hose Clamps,For Motorcycle Kawasaki Kohler Briggs Stratton Small Engines,Boat Marine Outboard Gas Diesel Petrol : Everything Else Amazon.com: NEW DAFU 1/4 Inch 6mm ID NBR Nylon Braided Fuel Line Set,10 Feet+20 Pcs 2/5 Inch ID Hose Clamps,For Motorcycle Kawasaki Kohler Briggs Stratton Small Engines,Boat Marine Outboard Gas Diesel Petrol : Everything Else

Amazon.com: Swpeet 100Pcs High Temp Silicone Rubber Protective Tapered Plug Assortment Kit, Masking System Kit Perfect for Powder Coating, Painting, Anodizing, Plating & Media Blasting : Automotive Amazon.com: Swpeet 100Pcs High Temp Silicone Rubber Protective Tapered Plug Assortment Kit, Masking System Kit Perfect for Powder Coating, Painting, Anodizing, Plating & Media Blasting : Automotive
 

Last edited by Belloc42; Jan 12, 2023 at 09:44 AM.
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Old Jan 12, 2023 | 01:34 PM
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I am thinking about running the hose up and to the front and then down to a can or filter as shown by the red line.. Does any one see a problem in running it this way?


 
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Old Jan 12, 2023 | 02:04 PM
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Originally Posted by Ken45
I am thinking about running the hose up and to the front and then down to a can or filter as shown by the red line.. Does any one see a problem in running it this way?
Opinions seem to differ on this, but I note that the tubes inside the filter housing (on mine, anyway), rise before they fall. Whether a larger rise holding more goo would make it back up, I don't know. I haven't seen anything definitive, and I researched this quite a bit before doing mine.
 
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Old Jan 12, 2023 | 02:06 PM
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It seems like the hose should always go down, I'm not sure it it will pump the gunk uphill.
Hopefully someone with more knowledge will chime in.
 
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Old Jan 12, 2023 | 04:09 PM
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When I ran the stock housing I purchased a couple feet of hose, union and hole plug. ran it out a drilled hole in the bottom of the housing.

These days I run the Trask setup
 
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Old Jan 13, 2023 | 02:00 AM
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I did it the cheepie design. In the pics, that SS braided line is very inexpensive, plumbing section at Lowes, Ice maker water line.

smaller line is oil pressure they meet up and head our together

The larger line turns under the can cover, runs along the frame, then into a 90 just behind the cross member
 

Last edited by dfixit1; Jan 13, 2023 at 02:02 AM. Reason: extra thought for reply to quote
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Old Jan 13, 2023 | 02:05 AM
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Originally Posted by dfixit1
I did it the cheepie design. In the pics, that SS braided line is very inexpensive, plumbing section at Lowes, Ice maker water line.

smaller line is oil pressure they meet up and head our together

The larger line turns under the can cover, runs along the frame, then into a 90 just behind the cross member

That big-ole air cover hides a bunch.
 
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