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RF Whatley
RF Whatley
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Breather pipe to airbox
#767973 03/13/19 3:02 am
Joined: Oct 2008
Posts: 6,247
Likes: 22
DavidP Offline OP
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Mine is trashed.
I have read the opinion that routing the crankcase breather into the back of the airbox is bad practice.
So, what do y'all do? Pipe the breather into the air and plug the hole in the back of the airbox?


Stepping on others doesn't make you stand tall.

71 A65L "Zelda"
92 BMW K100rs "Gustav"
72 T120V cafe project "Mr. Jim"
72 T150V "Wotan"
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Re: Breather pipe to airbox
DavidP #768002 03/13/19 1:19 pm
Joined: Feb 2007
Posts: 859
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David,
On my '71, I tried a lot of different things with the breather over the years. What I ended up with is keeping the stock connection to the air filter, but replacing the bolt in the front of the engine that gives access to the crankshaft for statically timing the ignition with a hose barb. I then ran a hose up under the tank and seat and out the back. You can feel pressure and vacuum at the hose, but I don't get any oil coming out. I am not getting any significant oil in my air filter either.
One issue with getting rid of the stock hose is its size. Its too big to easily run out the back. Years ago, I tried putting a reducer on it to let me use a smaller diameter hose. Predictably, that just resulted in immediate multiple oil leaks.

Ed from NJ

Re: Breather pipe to airbox
DavidP #768009 03/13/19 5:06 pm
Joined: Feb 2008
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When I bought my 1972 T150V in early 1973 direct from the Development Shop at Meriden I took the (unofficial) advice from Alan Barrett (RIP) who was the Development Shop Foreman.
He advised me to block off the entry to the air filter and run a full diameter plastic pipe to the back of the rear mud guard (fender).
Reason?--- as the engine wears it will breathe more oil and eventually block the air filter with oil.
The configuration he recommended was used I believe on the triple racers in the early 70s.
I followed the advice and have had no problems with it.
Still have the bike--46 years later!

Re: Breather pipe to airbox
DavidP #768019 03/13/19 6:40 pm
Joined: Dec 2013
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DOPE
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DOPE
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i used a piece of radiator hose and a K&N PCV filter on mine.

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every day you do not take a chance is a day of your life that you will never get back.
Re: Breather pipe to airbox
DavidP #768107 03/14/19 3:30 pm
Joined: May 2005
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I did similar on my T150V when I went with K&N air filters


When given the choice between two evils I picked the one I haven't tried before

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