Author Topic: Long stroke A7 breather question  (Read 2577 times)

Offline Ron B

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Long stroke A7 breather question
« on: 12.05. 2011 18:14 »
I have a 1949 A7 that blows a bit of oil out of the breather.  There is no breather pipe up there, just a hole.  Does anyone have a clear picture (digital not drawing) of what the breather assembly is supposed to look like.  I suspect the rings allow a bit of blowby but this is getting kind of messy.  I would like to run this breather back to the oil tank if possible.  Any pictures or advice will be appreciated.  Ron B
1949 A7 Long Stroke
1950 B31 w/ M21 engine
1954 A10
1967 BMW R60/2

Offline BSA_54A10

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Re: Long stroke A7 breather question
« Reply #1 on: 13.05. 2011 09:29 »
It is nothing more than a pipe with a flare on one end & a flare nut to hold it into the cases.
Some are just jambed into the hole.
The breathing is done by the spindle inside the timing cover with the thick cork washers around it.
The outlet is just that, an outlet
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Online bikerjohndavies

  • John Davies, Bath, UK
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Re: Long stroke A7 breather question
« Reply #2 on: 13.05. 2011 10:07 »
As BSA_54A10 said it is just a pipe that pushes into the hole at the back of the crankcase and held by a clip at the bottom to a crankcase stud. Here is a picture of one as I have my cases out of the bike at the moment. The cases are upside down looking from the rear.
1931 Ariel VB31, 1935 Triumph 5/3 project, 1946 Ariel Square 4, 1952 Norton Model 7, 1953 BSA A10 Super Flash, 1954 Ariel VH

Offline shabashow

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Re: Long stroke A7 breather question
« Reply #3 on: 13.05. 2011 16:25 »
My one (52 A10 plunger) is just a wee short piece of copper tubing, not a long one like bikerjohndavies. It's positioned perfectly to keep my chain well lubricated.

Offline BSA_54A10

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Re: Long stroke A7 breather question
« Reply #4 on: 14.05. 2011 10:34 »
It was when it left the factory
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Online bikerjohndavies

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Re: Long stroke A7 breather question
« Reply #5 on: 09.07. 2015 08:47 »
I would like to revive this topic as I am now thinking I may have the wrong crankcase breather (top hat) in my long stroke. There is a strange regular blowing/sucking sound that can be heard at low revs as well as oil coming out the breather which I have so far ignored but I now want to do something about. I know that the cam pinion for the long stroke has the pin for the top hat directly above the key slot which is different to the later ones so I guess the early breather also had the hole for the pin in a different place. The long stroke and short stroke breathers have a different part number so I wondered what the difference is.
1931 Ariel VB31, 1935 Triumph 5/3 project, 1946 Ariel Square 4, 1952 Norton Model 7, 1953 BSA A10 Super Flash, 1954 Ariel VH

Offline 1949BSA

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Re: Long stroke A7 breather question
« Reply #6 on: 27.07. 2015 15:43 »
On my 1949 Longstroke I have also trouble with the breather. When the bike is standing in the garage, oil is leaking from there.
I think there is a cork ring inside and, may be, it is not tight enough anymore.
Is there an easy possibility to renew the cork?
When the bike is running, I can not see any oil dripping.

Michael