Hi everyone
re 5 Hp Vanguard, have had one for 12 years on apush Big Bob
great device, then started to blow off breather and smoke likea steam train,
pulled it down , bore perfect, rings no gap, did not take off oil ring but
top ring brand new, piston like new,
anyone any clues, heard it could be the breather but it is just a flat disc,
seems ok.

Regards

Assuming this is a single-cylinder engine, sure sounds like the
breather valve, etc. has failed. Or you've been running it a strange
inclination.

I'd replace all gaskets and whole breather.

HTH,
J