Breather tube sizing - MK1

[Roger Gwynn]

I hadn't realized that there was that much water produced when burning petrol, presumably this comes mainly from the air unless you are using contaminated petrol and will vary with humidity. The breather problem when running with a Morgo stems from the sheer volume of oil being pumped round the engine, there is at least one owner who apparently suffered with an oil tank that was distorted due to the pressure, which I find hard to believe and I don't have 1st hand knowledge of that. Bruce recommends running with a reduced oil level in the oil tank when a Morgo pump is fitted for that very reason. The problem with the original pump is not the quantity of oil or the pressure but the reliability of the pump

[nevhunter]

Roger ,It's Nothing to do with humidity. With a HYDRO-carbon fuel, each H2 picks up one oxygen from the air forming H2O and the Atomic weight of O is 16. This is what ruins vehicles that only do short runs. WATER in the oil. I can't see why the high volume of oil can be the whole cause as it has a Pressure limiter relief valve, Oil is never vaporised unless something BAD has happened like with a large Plain bearing failure and lots of heat. Nev

[simon.holyfield]

Hello Cam,
I've no experience of using a larger i.d. breather on a Square Four, but I do wonder that, if you are losing too much oil through the existing one, have you considered routing the pipe from the back of the timing case upwards rather than downwards? A flexible hose can then be led to the back of the bike.

My thinking is that a vertical rise from the breather would allow condensed oil vapour to drain back down into the engine. I haven't tried this on a Square Four, but an upward-routed breather hose is standard on my Commando. Any thoughts?

Allan.

Anyone ever done this? Sounds like a good idea to me.