Air vent r 25/2

Begonnen von Anto, 04 Juli 2018, 12:28:32

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Anto

Hello, someone explains to me how the air vent of the r25 / 2 really works considering also that it is fixed on the tree in a "strange" way: a screw, a spring, a pin and no bearing since it is narrower than the seat of the cover. Thank you

Anto


bwprice100

Hi Anto

Part number 4 in this diagram lifts like a pressure cooker against the spring and then crank pressure is released.

Brian

https://www.realoem.com/bmw/enUS/showparts?id=0T12-EUR-03-1952-T25-BMW-R25_2&diagId=11_2596

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Anto

Hi Brian,
thanks for the quick reply. Now it's clear!!!  :juhuu:  But anyway because the system is fixed in that strange way: with the bolt screwed to the maximum the piece "4" moves the same then because the only pin "5"?
Thanks for yesterday's greetings

bwprice100

You are welcome


Pin 5 keep the slots on part 4 in alignment so the pressure is released at the correct time.

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Anto

I mean they could make it solid and precise with at least two pins.
I do not think they wanted to save money on such a trivial variant

bwprice100

Yes there are lots of things where l also ask the question, 'why did they do it this way' but l think some of these design features go back to before 1938. :)

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4Taktix

#6
Hello Anto,
the Pin 5 is to have a certain position of Part 4 on the Chainwheel 6.
So the sideholes in the protruding tube of Part 4 open the Outlet-Channal (in the Timing-chain cover) at the right moment. After the Piston came down
and created a slight pressure in the housing.
It is not desired to suck from outside into the crankcase whilst the Piston goes up and creates a vacuum.
Regards,
Sascha
Brian was quicker ;-)
Think outside the box !

bwprice100

Zitat von: 4Taktix am 04 Juli 2018, 16:07:19
Hello Anto,
the Pin 5 is to have a certain position of Part 4 on the Chainwheel 6.
So the sideholes in the protruding tube of Part 4 open the Outlet-Channal (in the Timing-chain cover) at the right moment. After the Piston came down
and created a slight pressure in the housing.
It is not desired to suck from outside into the crankcase whilst the Piston goes up and creates a vacuum.
Regards,
Sascha
Brian was quicker ;-)
A better explanation. :)

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Anto

Hi Sascha,
  I had doubts especially when I disassembled the piece and had only one pin. I'm trying to understand why fixed in this way qusi eccentric if you move it because of the spring that does not oppose so much resistance .... could damage the seat?

rolf

But it become concentric  when assembled....
with only 1 pin it not so expensive to get it concentric (see above)....and it is not necessary... the guide of the hole was good enough

4Taktix

Part 4 ( "Entlüfter" ) is guided in the Timing-Chain cover! ( like a slide-bearing, floating on an oil-film )
I suppose that it is fixed as it is, to have some side-movement to make it easier to mount the Timing-Cover. At least this sounds plausible to me.
If anyone knows better, please shed some light on the "why" ;-)
Regards,
Sascha
Think outside the box !

Anto

Exactly, the oil film would be the most plausible explanation but unfortunately I think there is a lot of oil in that part: it would lose it from the hole ... or not. Come on, let's see if there could be other explanations.

rolf

in this part is only "oil fog".....if there is more, something is wrong

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