Needing Air

you already have a multi topic thread on the go that like this thread end up going on and on then inevitably to mostly gibberish and irrelevance,

perhaps you would follow your own preaching and stick to a topic in a thread that you begin,

otherwise at best, you are dreaming, this topic (below) and thread was done awhile ago, and prob went nowhere like this one

your first post talks about a breather and the first post sets the tone for the topic and what the thread should be about

Combat crank case breather.
Teardown of my Combat engine prompted a review of my current breather system. This utilises a 4-reed one-way valve after the LH case mounted breather tower to positively evacuate air and oil away from the crank cases. A catch can then separates air for venting and oil for return to the oil tank using engine vacuum.

My improvement removes the 4-reed one-way valve and better utilises the breather tower to create a one way valve at the crank case exit. Calculation of breather tower ingress, seating and egress ports shows no restriction to maximum air and/or oil flow. Resistance to flow within my improved system is 13g and provided by a single 9/16" steel ball seated within the tower body. Additionally, a stainless steel ball or two balls in the tower may be used to modify resistance, if desired.
One of two convex steel mesh discs was removed (from the breather tower body) but the cap disc is retained to prevent the ball from potentially seating into the cap. The cap mesh has been magnetised to further enhance removal of metallic swarf from the system. Magnetising the steel ball was considered but this may compromise the ball's seating ability if it was contaminated with swarf.

To verify calculations, the dimensions are (mm):
Inlet ID: 18.5
Seat ID: 12.25
Body ID: 19.1
Outlet ID: 12.8
Ball OD: 14.28
Weight: 13 gram

The 9/16" steel ball cost AUD$1.00.

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Thank you for your input 84ok.
The title is 'Needing Air' and the subject matter is Norton Commando airflow in its multitude of forms - currently Mk 1 AMALs.
I hope that helps clarify your thoughts regarding my thoughts.
Ta.

you can do what you like, i don't see "the subject matter is Norton Commando airflow in its multitude of forms" in the first post
and even if it was, it's a multi topic can of worms where you will never have order,

you could start separate threads that focus on any one of the "multitude of forms" of interest,

otherwise you will end up with gibberish just like what this thread has become, and anyone who may be interested or looking in to a particular topic of interest will quickly find blah blah aplenty, tune out and move on

no way you're gonna get a focused thread if it's about "Norton Commando airflow in its multitude of forms", sounds like at the least, a multi chapter book

Thank you again 84ok.
Did you find the experiment regarding airflow across spray nozzles using different slides of interest? If you think I have overlooked anything please let me know.
The vacuum cleaner I used could only achieve about 6 inHg with constant flow but in real life the manifold vacuum is nearer 20 inHg and pulses 1 in every 4 piston strokes. I think the pin holes have been largely overlooked in decades of AMAL Mk 1 discussion and I have now made them 'work' by effectively sealing the throttle slide lip. Perhaps you saw the video of my bike idling without any use of throttle stop screws?
Ta.
Edit: I do try to avoid, even hide from, the blah blah but sometime even I find it too ludicrous to ignore. I'm still learning...

i tune into threads that show focus and find the best info comes where the topics and info is discussed in the fewest words,

i've barely glanced at this thread and am done with it, but good luck

There is no sense to motorcyles, especially over 250 cc - so let the hot air flow as it may. Its obvious who is regularly taking the fun out of this breeather and exploring Amal function. It is about motorcycles, especially one over 250 cc so of course a complete waste of time to spend negative emotional reactions on.

Rohan said:

So is Mr Healey spinning us a yarn then about the purpose of the stepped spray tubes - and Ludwig following in his footsteps !
Leaning it out to solve a flatspot just seems soooo wrong, ESPECIALLY in the new larger motor.

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In an earlier thread , I already said that John Healy no longer stands behind the explanation he gave ( the one LAB and I quoted ) on the Britbike forum .
Why don't you ask him ?
That the stepped tube was introduced to cure a flat spot is a myth .
I think I will start a separate thread ..

Re: Needing Air up and over pin holes

Some more science from the 21st century...

An AMAL 32mm (1_1/4") carburettor throat was connected to a vacuum cleaner.
All body orifice that could leak air were sealed except the carburettor throat.
The pilot circuit fuel intake orifice was blocked.
A gauge was fitted to the pilot circuit air intake orifice.
The pilot circuit air intake mixture screw was turned out 3 x ½ turns from fully seated.
All throttle slide orifice were sealed so air could only pass beneath them through the throat.
A standard 3.5 cutaway alloy slide and a polymer 3.5 cutaway slide with fitted air flow channels were used.
The spray nozzle fitted was the stepped type.
The vacuum cleaner function was not re-assessed but is assumed consistent with yesterday’s trial at about 6 inHg.
When fitted, a throttle slide was initially fully closed to determine the vacuum generated with air passing through the pilot circuit pin holes. The throttle slide was then raised to determine when the greatest Bernoulli effect was achieved across the pilot circuit pin holes.

Result:
Maximum Bernoulli effect occurred with either slide type set at 1.5mm (0.060") i.e.
1. at 5% of throttle slide opening, or
2. equivalent to 3mm arc rotation of the throttle grip.
Once maximum Bernoulli effect had been achieved, it remained constant up to the limit of the trial at 6.5mm of throttle slide opening.
The attached photos show the set-up and achieved results.

Conclusion:
1. The polymer slide with fitted air flow channels showed significantly increased Bernoulli effect compared to that generated by the standard alloy slide.

You may now also quote/misquote/misrepresent/fabricate stuff based on the above for decades to come!
Ta.

Pretty neat result, but if only we could resist not opening more so fast.

Re: Needing Air up and over pin holes

needing said:

Some more science from the 21st century...

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Its not entirely obvious what you are actually testing here ?
More pics or more words required ?

And we have noticed your penchant for declaring anything or anyone that even slightly disagrees or questions you in even the slightest way to be 'irrelevant',
so I guess we are irrelevant again....

ludwig said:

In an earlier thread , I already said that John Healy no longer stands behind the explanation he gave ( the one LAB and I quoted ) on the Britbike forum .
Why don't you ask him ?
That the stepped tube was introduced to cure a flat spot is a myth .
I think I will start a separate thread ..

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Not quite enough words, or precision, to be entirely sure exactly what this means.

Mr Healey is quoting a myth, dispelling a myth, denying a myth, or generating a myth ???

hobot said:

Pretty neat result, but if only we could resist not opening more so fast.

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If you've ever opened the throttle on a pair of pumper delortos Steve, that surge of power is delicious.
Haven't tried it on an 850 C'do lately, but those cutaway spray tubes do the same function. (?).
We can't even seem to agree here if they do or don't.... ???????????????????????

My FCRs have accelerator pumps on them and the acceleration is indeed delicious. However, I haven't tried them with the pumps disconnected to compare.

However, as was alluded to earlier, it is my thinking that the pumps role is largely to allow for a wider throttle opening than the carb would normally allow for. So I doubt it is over richness which gives the good acceleration, and is more to do with allowing a wider throttle opening than would normally be 'intuitively correct' for a short 'burst' of overly wide throttle opening.

Rohan said:

Mr Healey is quoting a myth, dispelling a myth, denying a myth, or generating a myth ???

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Rohan :
Mr Healy is highly regarded as an expert on Amal carburettors , but he is not the oracle .
The only reason for me to quote him , is to demonstrate that there are conficting opinons .
And now I will leave this thread to Needing and his experiments .

Re-ran the pin hole trial again late yesterday to review why airflow increased through the pin holes simply by using the plastic throttle slide compared to the alloy one. I thought they should be the same regardless of slide material or design as the pin holes diameters and applied vacuum are constant.
The result was the same as the first trial.
The only logical conclusion I have drawn is the plastic slide seals better in the throttle body bore compared to the alloy type.
Ta.

When are you going to try these 'plastic' slides in an actual engine.
And jiggle with the jetting to suit.
The proof of the eating is in the pudding, so to speak.

Tell more of these slides too, many plastics don't like hydrocarbon solvents anywhere near them... ?

We learned to select a test gauge so that it would read center range of the experiment. Your tests are so low on the gauge that I can't learn anything from the data.
Jaydee

jaydee75 said:

We learned to select a test gauge so that it would read center range of the experiment. Your tests are so low on the gauge that I can't learn anything from the data.
Jaydee

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Thanks Jaydee.
So did I but that gauge is the only one in the cupboard that came anywhere close. As you may know, the higher the discrimination = the higher the cost. I will gladly repeat the trial with a 'better' gauge if could see see yourself clear to contributing toward purchase (perhaps the crowd-funding model will be how I equip my shed with all the equipment and gauging I wish I had).
Ta.

DIY manometer with various fluid density can match the pressure task.

https://www.google.com/?gws_rd=ssl#q=ho ... 0manometer

I think Jaydee means the common engineer practice regarding mechanical gauges is that the top 10% and bottom 10% are generally regarded as far less accurate. He can correct me if I am wrong, but it is not the discrimination, but the absolute value that is in question.

needing said:

jaydee75 said:

We learned to select a test gauge so that it would read center range of the experiment. Your tests are so low on the gauge that I can't learn anything from the data.
Jaydee

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Thanks Jaydee.
So did I but that gauge is the only one in the cupboard that came anywhere close. As you may know, the higher the discrimination = the higher the cost. I will gladly repeat the trial with a 'better' gauge if could see see yourself clear to contributing toward purchase (perhaps the crowd-funding model will be how I equip my shed with all the equipment and gauging I wish I had).
Ta.

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