Author Topic: Breather pipe  (Read 602 times)

Offline TT John

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Breather pipe
« on: 21.05. 2019 10:44 »
Hello all.

Hoping for a bit of input here, I have just removed the primary chain case & found behind, on the engine crank case just below the barrel stud, a hole which had quite a bit of oil around & below it, which has lead me to believe that there should be a pipe attached, I'm pretty sure it's the breather but there is no mention of this in the manuals that I have. I have been getting a leak from the back of the chain case which I initially thought was gear box oil seal, behind the sprocket. *????*

TTJohn

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Re: Breather pipe
« Reply #1 on: 21.05. 2019 11:32 »

 Yep that's exactly that- the engine breather outlet.
 I have a length copper tube and plastic hose attached to mine feeding to a catch bottle, but realised the other day that the hose is rubbing on the chain which made a hole causing an oil leak.....so if you figure it out I'm all ears (with not much betwixt),,,,,,,,, *conf2*
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Online orabanda

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Re: Breather pipe
« Reply #2 on: 21.05. 2019 12:19 »
I usually make up a pipe & install as per pics below.

It provides control of oil that comes out of the breather, but prevents the "natural" lubrication of the drive chain that the practical people at BSA probably had in mind.

Richard

Online ellis

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Re: Breather pipe
« Reply #3 on: 21.05. 2019 14:04 »
Hi TT John.

Yes it is a breather hole. On my 1960 A10 Gold Flash i fitted a small length of copper tube and bent it to point onto the the gearbox sprocket to provide the chain with a bit of oil. It worked a treat.  *smile*

ELLIS

Offline TT John

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Re: Breather pipe
« Reply #4 on: 21.05. 2019 20:25 »
Yes found it, it is the breather pipe, I managed to salvage one from another engine, just a push fit. curls round the crank case secure with a P clip at the bottom, with a very small hole in it which is intended to lubricate the chain. Thanks for the help lads.
Anyone going to the Open day at Mkt Harborough this weekend? If so I will see you there.


Regards TTJohn

Offline RayC10

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Re: Breather pipe
« Reply #5 on: 22.05. 2019 18:35 »
Am I right in saying that the plunger engine had a pipe as standard but the s/a had just a hole? I stuck a pipe in mine as well

Offline Russ

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Re: Breather pipe
« Reply #6 on: 25.05. 2019 00:42 »
While we are on the subject, is the pipe sealed into the engine?
Russ
1951 A10 Plunger.
Australia

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Re: Breather pipe
« Reply #7 on: 25.05. 2019 04:32 »
No they are shrunk in
Bike Beesa
Trevor

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Re: Breather pipe
« Reply #8 on: 25.05. 2019 09:16 »

 
Quote
While we are on the subject, is the pipe sealed into the engine?
Russ

 
Quote
No they are shrunk in

   *conf2*

 Doesn't that more or less mean the same thing ?
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline Russ

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Re: Breather pipe
« Reply #9 on: 25.05. 2019 10:37 »
No they are shrunk in.

How is it shrunk in




1951 A10 Plunger.
Australia

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Re: Breather pipe
« Reply #10 on: 26.05. 2019 09:18 »
Pipe is chilled and the engine is run till the cases get to operating temperature.
The pile is inserted then the whole shooting match is allowed to cool down
When chilled the tube should still be a tight fit in the hole or you risk it falling out into the chain.
On some there were P clips on the rear of the chaincase.
Bike Beesa
Trevor

Offline Colsbeeza

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Re: Breather pipe
« Reply #11 on: 27.05. 2019 07:39 »
Hi Trevor,
That means that the OD of the copper tube must be exact. What diameter is the tube.? I have read somewhere on the Forum that it is "about" 8mm. Did you need to machine down the tube end.? I am re-assembling my Flash and want to fit a tube also.
Col
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Offline Swarfcut

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Re: Breather pipe
« Reply #12 on: 27.05. 2019 08:01 »
Col. Its just a copper tube in a hole. How they did it in the factory does not matter, all it needs to do is stay in the hole. So, on plunger engines sometimes the pipe ran down the back of the crankcase, secured by a P clip on the through crankcase stud. This meant all the  oil drips from the sump plate joined those from the breather. Some Plunger engines have a very small pipe which leads back, secured under the the part of the casting covering the chain, effectively dropping the drips on the chain to do some good. Originally the pipe was were sealed in, probably with some sort of varnish.  Dip in the glue, knock it in, bend, bolt, next....

 You just need some thin wall tube which fits nice and snug in the hole, sealing and securing with modern Loctite, even epoxy or cyanoacrylate glue will also be fine, if you want true perfection.

   Where it goes is up to you, but leading it down to the rear of the gearbox sprocket, to oil the inner side of the chain, is a good plan. Make sure it is well supported.

 The  excellent pictures above show attention to detail that I can only envy, so aim for something like that.

 Thinking about S/A motors I reckon most are just a hole....at least it stops the chain guard joint squeaking, and prevents rust....another masterpiece of cr*p design.

 Swarfy.

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Re: Breather pipe
« Reply #13 on: 27.05. 2019 08:08 »
Hi Trevor,
That means that the OD of the copper tube must be exact. What diameter is the tube.? I have read somewhere on the Forum that it is "about" 8mm. Did you need to machine down the tube end.? I am re-assembling my Flash and want to fit a tube also.
Col

Long long time ago but I made up a nipple to fit into the hole very tight then used cheap pvc tube pushed over the nipple.
Had a copper tube fall out at near a ton, not pretty & took a month to get the stains out of the undies.
Bike Beesa
Trevor

Offline Swarfcut

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Re: Breather pipe
« Reply #14 on: 27.05. 2019 08:58 »
   Nice one, Trev, an even more versatile idea with plastic. Yup, that oil gets everywhere.

 Regards

 Swarfy.