1952 BSA A 10 Breather issue

[Nadun D]

Hi all,
This is my first appearance and I am from Sri Lanka
I have recently buildup my 1952 A 10 plunger engine with 67-334 cam( used but fairly ok with every aspects).
 1. Soon after first start (11/32 inc BTDC) yellow flame with white smoke came from left exhaust and plug was oily. 2.Apparently piston top wet with oil! Major issue was breathing seems not proper and huge air escape from primary cover inspection cap hole and white smoke from breather and primary when engine heat ( like under compression but not)
3. I had to dismantled the top end and place new oil rings with gap of 12 thou and 13 thou for other rings. Still oil on both piston top and breathing issue remains the same.
4.Breather timed ok and no play of the breather cork washer. No crank play or anything noted. Breather hole seems ok.

5.Now I stripped the whole engine (yet couldn’t find any problems) and think about to place 356 cam as the engine was noisy on first appearance!
( Bike ran well and good power, doesn’t seems compression lost with all these issues, I assumed due to breather malfunction pressure in side the crank case cause oil escape from oil rings due to breather?? )

This is my second 52 engine rebuild and first came without any issues and running well.
(Brand new unnamed pistons brought from UK )
Have I missed something bad?
Appreciate any help on this
Nadun

[Greybeard]

I hope you cleared out the sludge from the crankshaft trap🤞

[berger]

Nadun D it might be worth checking your rings in the bores because there was a lot of bad ones about .i know this because my new build was chucking neat oil out and on inspection with lightly using engineers marking blue in the bores and pushing the rings down with a piston there was high spots on the rings . i bought some more rings made by gandini and they were perfect curing my problem.

[Nadun D]

I hope you cleared out the sludge from the crankshaft trap🤞

Yes I completely removed and cleaned!

[Nadun D]

Nadun D it might be worth checking your rings in the bores because there was a lot of bad ones about .i know this because my new build was chucking neat oil out and on inspection with lightly using engineers marking blue in the bores and pushing the rings down with a piston there was high spots on the rings . i bought some more rings made by gandini and they were perfect curing my problem.

Good to hear, yes I changed my rings now twice apart original.

[muskrat]

G'day Nadun.
Oil on top of the pistons could be coming from the inlet valve guides or head gasket.
Cheers

[Nadun D]

Yes I am planning to double check, but this problem seems due to high crank case pressure due to malfunction breathing. Air escape from primary inspection cap hole and smoke as well when engine hot!

[Topdad]

Hi have you re[
placed the cork washer fitted inside the inner timing case should be tight if my memory is right hope you sort it