903,000cc looks more like 903 litres to me. As for the hose idea, I'd like to see someone prove that, but not on my engine.

Joolz,
glad someone could be bothered to check Harley's maths, as that throughput of air did seem rather high for a little engine.

I was wondering how many 45 gallon/200 litre water barrels that 9,000 litres/minute would be...

4-stroke combustion engine calculations require the rpm be divided by two since air is exhausted from the cylinders every second revolution (Canadian Automobile Association, 1983). A 4-stroke engine with one litre displacement operating for 60 minutes at 2,500 rpm is estimated to consume 1 L × 2,500/2 rpm × 60 minutes = 75,000 litres of air.

From this site; http://ptaff.ca/air/?lang=en_CA

ken

Hi guys,
Sorry for the absence .

I agree with your comments. It cannot give such a big pressure but the air is cooler and most important, eneryone is wondering.

The water check valve, bought from a general wardware store for central heating use, is there for only 600Km and I will dismandle it at 1.000km.
Note that the reniflard is still fitted but gives alone only 1-2cm WC at idle.

even if you use a spray bottle it falters - great way to soften up the clinker if your about to do a decoke

Had the same fitted to my 'A'series for about 18 months, have not got round to any vacuum tests,but I seem to use/loose less oil, with less in the air cleaner.So I'm just leaving it in situ as it can only assist even if it's only a little and loads cheaper than the valve from ECAS and the like, which at the end of the day is just a one way valve

Ever felt the pulse of air in a Dyane's air box even at idle? At 6,000prm it will be quite a blow, aided by the car's forward motion.

There's a good reason tuned cars use carefully designed air intakes which take full advantage of the ram effect.

But, if you blocked the pipe between the breather and the air filter box, that would have the same effect, wouldn't it?

The higher the vacuum a one-way valve can create, the more oil there's likely to be in the air filter box.

Something which doesn't seem to have been mentioned previously.
A breather system which is functioning as it should will minimise contamination of the engine oil by expelling blow-by gasses before they have a chance to condense in the crankcase...

ken

Do not forget that the reniflard is designed to drain the oil , back to crankcase.

Now thats a very valid point. All these quick fix gadgets chokes with oil quickly and stops proper crank vacuum
If the original design (reproduction) is working why bother farting around looking for trouble.

As the reifllard is still in circuit it is still doing the job as intended even if the flapper valve isn't.Oil mist is going to condense and drain back as intended,the tube that goes upto the aircleaner,is there to suck the fumes back into the engine.I can't see that a one-way valve is going to change any of that apart from creating a little more ( very little) vacuum.

The valve I have opens with very low pressure, before I fitted it this was one of my concerns which I checked by blowing through it and it only took a very small puff to do so,whereas the closed state is designed to stop mains water pressure!I have had it off to check that all is well after being fitted for over 12 months,having made two trips from UK to S.W.France in very high temps over long time,distance and at cruising at 60-65 mph.The valve having suffered no ill effects and still functions as when I fitted it.I get 50 mpg to boot

Having build and designed high vacuum systems many years ago I am quite happy to leave it in place as I have found all is well.I will continue to make the condition/function check as part of my service routine.