New Member from Nuneaton

[easyal]

Hi All
I'm presently repairing a 1957 A10 which i've owned for 6 years - a heavy breather and no dynamo output.I was very interested in all your breather stories [mine also has a rocker box vent from a earlier owner]
Just repaired forks,new clutch plates and fitted electronic ignition system within existing mag housing.
I am now thinking of blanking off the rocker breather,what is the recommendation.

Also have a 1966 t/bird on the road which I restored 10 years ago.
Regards Alan

[bsa-bill]

Hi Alan and welcome

I'm sure you will get plenty answer and help here

Breather - definitely two schools of thought, I'm for leaving things as BSA intended as I have never had a breather problem but there again I don't thrash the motor at all really and maybe at high revs there an issue,  I wouldn't know.
I do make a point of clearing drain holes from the head and barrel when assembling to ensure there is room for pressure to release through the engine

All the best with it

[LJ.]

Hi Alan... Nice of you to join us!

Non of my bikes have additional breathers.... If one is needed then it suggest that there is a problem somewhere and needs investigating. Try blanking it off and keep a watchful eye on things and see what happens.

Cheers! LJ.

[muskrat]

G'day Alan, welcome.
                                  I have one on either side of the fence. My '51 A7 breaths normally and I have no problems with oil leaks or heavy breathing.
My '57 A10 is highly modified and I found marked improvements to acceleration and top revs with the use of the Bunn breather system where the timed breather is eliminated. It sucks in fresh air via the rockerbox and exhales through the standard breather hole in the LH crankcase.
With a rockerbox breather the timed breather will not work as intended and most of the breathing will be in and out of that one hole.
Cheers

[easyal]

Can you describe the Bunn breather? Don't suppose it will fix my breather oil loss that would be too easy!
Regards Alan

[Goldy]

Hi Alan and welcome. I live in Nuneaton we will have to get together some time. You will find plenty of knowledgeable and helpful guys on this forum. All the best Goldy.

[muskrat]

G'day Alan,
                  oil loss out the breather can be caused by too much oil in the cases eg wet sumping overnight or scavenge pump not doing it's job properly. As well as too much blow by the rings increasing crankcase pressure. The Bunn would help with the latter but not the oil. It is basically two one way valves. One allowing fresh air in and the other letting bad gas out. Read about it here http://www.bunnbreather.bigblog.com.au/index.do I have no connection but like his product.
Cheers