Breather-Tank

[peter]

My BSA Goldflash A10 1954 loses als all other oil from breatherhole.I built from stainless steel an small breather oiltank, I mounted it below the motorcycle frame. I installed an copper breather-tube from breatherhole to the breather oiltank.Breather oiltank has an outlet to the street.
It works very well, my bike is`t losing oil on the floor anymore, yupee!

[bsa-bill]

neat solution Peter, Photo would be nice when you can.
Well done

[lawnmowerman]

Hi Peter and welcome to the forum.
Very tidy and innovative fix - much better than running a pipe to a beer can taped to the footrest bracket which we used to do back in the day 

Jim

[A10Boy]

Hi Peter and welcome.

I was just wondering, are you sure your camshaft timed breather is working OK? The cork washer should be compressed behind the breather body, if it is loose it will blow all the oil out. Different thicknesses are available to get it right. Maybe it's worth checking if you haven't already done so.

[muskrat]

G'day Peter,
                 looks a lot better than my Golden Syrup jar.
Cheers

[peter]

Hello friends thanks for the compliments!!

A10 Boy; I know that has to be right breatherwasher, I think it is, there are only a few drops, I will not open the Motorcycle, but I no longer want to drop oil on the floor. For me is`t a great work to make an breather tank.

muskrat: you should take a guiness beer cans 

[dpaddock]

We should remind ourselves that the chief reason for the breather problem on all dry sump engines is the very small volume of the crankcase; pressure pulsations from the reciprocating parts, plus blowby as the engine wears, have no large space into which the pressure spikes can be attenuated. This is why the PCV valve which is sometimes fitted as an aftermarket solution doesn't really work on vertical 360 degree twins. If we could somehow enlarge the crankcase volume, the breather problem would be greatly diminished.

David

[iansoady]

Nice job; I'm glad to see I'm not the only one who doesn't like drips!

My current "solution" is merely to extend the breather backwards using flexible pipe but it's well worth bearing your mod in mind.

[BSA_54A10]

We should remind ourselves that the chief reason for the breather problem on all dry sump engines is the very small volume of the crankcase; pressure pulsations from the reciprocating parts, plus blowby as the engine wears, have no large space into which the pressure spikes can be attenuated. This is why the PCV valve which is sometimes fitted as an aftermarket solution doesn't really work on vertical 360 degree twins. If we could somehow enlarge the crankcase volume, the breather problem would be greatly diminished.

You can fit one of the Bunn Breathers to fix the problem for good.
Only downside is that you will have to make some holes in the cases and hide the tubes
In through the case & out through the rockers.
PCV valves do not work properly because they are designed to be opened by manifold vacuum not crankcase pressure.
If you really want to get into this all the info is here http://bunnbreather.bigblog.com.au. but it is not laid out very well so you need to scan through the lot then cherry pick out what you need to read

[muskrat]

G'day Trevor,
                  I love my Bunn breather. It has stopped most (ex rockerbox) oil leaks and motor spins freer. Oil will still escape out the breather if you have it (Bunn) exhausting that way, specially if wet sumped. I run a hose from the breather hose to the oil tank then use the Bunn to exhaust it. Mind you the cafe is a long way from standard (home made alloy oil tank).
 Peter, you say she looses all its oil out the breather hole. How long does this take ? You might have a problem with the scavenge side of your oil system.
Cheers

[trevinoz]

Trevor,
               I will differ from you on PVC valves.
If fitted in the correct direction, crankcase pressure easily opens them.
A friend used one in the rocker cover on his AJS twin and it solved his problem of oil being forced through the generator.
Trev.

[olev]

Gday,
A couple of years ago Erling stored the OBA article on the Bunn here.
http://www.a7a10.net/BSA/oba.pdf
He has lots of photos and good stuff hidden.
Is there an index somewhere?

cheers

[BSA_54A10]

Hi name sake.

Trevor,
               I will differ from you on PVC valves.
If fitted in the correct direction, crankcase pressure easily opens them.
A friend used one in the rocker cover on his AJS twin and it solved his problem of oil being forced through the generator.

We will just have to differ on this one.
I have been playing with Rex for many years so was in on the breather from the very start.
PVC valves will work up to a point, but I have seen both the tests and the data.
There are a lot of variables in the equation and a big one is the rider.

We have a member with a passion for B50's who thought that his PCV valve was working well till he put on one of the early test kits.
Now every bike he owns has a Bunn fitted.

A PCV may be sufficient under some circumsatances but it is far from ideal, particularly the flow through which is simply not enough as the bikes get up in the rev range. Brake valves did not cut the mustard either. If either did, then he would have just fitted one of them and be done with it.

When you have some time read all of the blog and if possible the refference material as well. There is a lot there. All this has caused me to rethink what I used to believe as well.

[dpaddock]

To our good friends in Oz, I hope you're not in the Brisbane/Toowoomba region just now. It looks devastating on TV!

David

[bsa-bill]

I'll echo David's thought on this, horrendous pictures on the media, must be totally heart breaking