A: Oil Pipework Breather back into oil tank

vibrac

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I hear what little honda says about venting from caps over valves but practical experience on the egli big bore where we had front exaust and rear inlet caps routed upwards to one way valves and down to a manditory 500cc catch tank which resulted in a spoonfull of R after a seasons racing leads me to endorse what many say engine condition is all.....
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27586
 

Little Honda

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David,
I always wondered, why Vincent twins are so very different from singles. Even Ernst´s short
stroke engine, which reaches 8000 rpm, shows very little sweat over a race weekend. The normal Comet racer
also does not collect any blow by in its bottle over a season.
His Lightning is relatively dry for a twin, ie, over a race weekend, it collects about 0,1l of mud in the collector,
but no oil. If there are long straights on track, she shows some mist here and there.
My Norvin (no race use) is so different: On a weekend trip over some 500 miles of riding, it is visibly oily and
drops, whereever parked, after arrival.
Ok, a motorway trip is a much longer time period of running to let the engine collect blow-by and add up
internal pressure, compared to a 15 - 30min race. In this point, blow-by seems to be an additive effect,
which remains non-critical at short time intervals.
You may be right, stating that blow-by is more at low speeds, say up to 1500 rpm. This is about the limit, until
timed breathing is effectiv. After this, you will need sufficient atmospheric breathing (as Honda uses everywhere) But, that is not the point: If it is right, when an engine is less gas tight at cold temperatures, than
at operating temperatures, this must be seen per working stroke, which means, that every single blow by volume adds to a total in your crankcase, depending on revs. Even , if your engine is more gas tight at higher
revs, it will add to a higher total pressure in your crank case due to double revs.
My impression is, however, that bow-by is worse at high revs at high engine temperatures, which is easier to understand, when thinking about how a piston ring works. His tightening abilities are more difficult at high
speeds, the more in the aspect, that the tightening force is mainly done by gas pressure from behind the ring.
The only reason, why a twin engine does leak more than a single, is - to my impression - that, per cyl.-volume,
the relating crankcase volume on a twin is smaller, than on a single. This could easily be measured, like bakers measure bread volume: by pouring poppy seed into a glas cylinder, in which lays the bread to be
measured.
This could also be done on any engine, but it must be dead dry inside, to get out again 100% of the poppy
seed to measure its volume.
Good, that at present times, bikes with "patina" are valued higher, than gleaming dream bikes, which I
could never afford....
 

Bill Thomas

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Why don't we hear more from Germany, Are they Modest !!, The web site you showed us the other day has a lot of nice stuff, If a lot of money !!.
Cheers Bill.
 

Little Honda

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Bill,
are you from Scotland? Regarding prices, you should note, that the Hegeler generator comes with regulator,
plus complete electronic ignition, all included, except plugs. Ernst never learnt English language in his lifetime,
so that is why there is not so much communication in this place.
I do that for him, when needed.
You can meet man and machine at the Caferacer Festival, this coming weekend. There you can see his Norvin
with his own engine in operation.
cheers, Little HOnda
 

Bill Thomas

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No welsh, just old and poor, l remember the old days, when this stuff was cheap.
Still think the d distributor is the way to go. + a Walkernator.
Cheers bill
 
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timetraveller

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I had a brief ride on the Hegeler 'Norvin' about three years ago at the Pioneer Run meeting near Dick Sherwin's. Although I only covered about four miles it was clearly a very nicely handling bike with a very useful electric start system. Ernst is a talented machinist and designer but does not like to fit his starter system to existing bikes as it means machining the original drive side crank case to get it to fit around the large starter gear.
 

davidd

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I wish I knew more about breathers. Frankly, when something works for me I don't pay it much attention any longer. I think that I said "blowby is worse at low speeds" but I should have said "windage is worse at low speeds."

David
 

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Little Honda

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Agreed, David. "Never touch a running system" is the saying. I discussed the problem of breathing twins with
Ernst today on the phone. His opinion was similar to your added article. So I suggested - to check, if the crankcase volume in Vincent twins is so much smaller, than on singles - simply to add a temporary tank volume
in the size of the standard crankcase volume, thus doubling it. This should show, if the twin engine under these
conditions would behave like a Comet. If not, some more thinking has to be done...
ps: this tank having no atmospheric exit, of course
 

Bill Thomas

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All you need is a big hole up high, With an oil separator, No catch tank !, My engines are race type and worn out, Like Me !. Cheers Bill.
 

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hrdaustria

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All you need is a big hole up high, With an oil separator, No catch tank !, My engines are race type and worn out, Like Me !. Cheers Bill.
good morning,
we are testing our recently finished three breather prototypes on a rapide, a comet and my shadow. the main focus was to lead the pipe downwards on the breather outlet as its mostly hided by the exhaust on twins. some of you have seen my shadow at the international, a dry bike. we´ve not yet found any oil leaving the breather pipe. no reed valve is used.
michi
 

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