ESE's works engine tuner

[senso]

That would explain the high reed cage and the clean-ness of the piston crown, but that would be sort of a uniflow engine, sort of cross-breeding uniflow and Schnuerle(I think this is wrong and there should be an umlaut somewhere) loop scavenging

[JanBros]

could it be Ryger finaly got an almost 40 year old idea working well tnx to better materials ?
but as the cylinder clearly has transfers, they just might have added this TVPS, it would certainly give some much needed time-area and reduce piston-mass for the higher revs.

from a magazine from 1977 :

[wobbly]

Cutting the piston skirt short on the Ex side has been done.
It was used to win a Jetski world title in stock class on a big twin with a common pipe.
It played hell with the jetting, but once we got the pumper carbs reset it made a shit load more power from the reverse
pulse coming back from the 180* cylinder finding its way down the paired header and adding compression to the exposed case
of the piston sitting at TDC.
I know nothing about any of this as its illegal as hell, but was never found in tech.

[Frits Overmars]

Frits, would the phrase " when reciprocating mass goes down , generally , rpm goes up". be correct?

Not necessarily. For example, a piece breaking off the piston skirt will not do the rpm much good, generally.
Joking apart, a while back I would have answered that the attainable rpm in a two-stroke is limited by the time.areas, not by piston speed or mass.
But that was BR (Before Ryger).

is it conceivable that a piston could be coated/ constructed with a known substance to withstand very high engine rpm/heat and be self lubricating, such as some known bearings that are available?

Whole pistons have been made from pressed carbon (the kind that carbon brushes are made of). Mahle experimented quite a bit with them, mainly for TDI engines, but they made some two-stroke pistons as well. They are self-lubricating and will withstand very high temperatures, but they are not much lighter than light-alloy pistons because they require thicker skirt walls, and their high crown temperature will provoke detonation, which makes them unsuitable for anything but diesels.

[husaberg]

could it be Ryger finaly got an almost 40 year old idea working well tnx to better materials ?
but as the cylinder clearly has transfers, they just might have added this TVPS, it would certainly give some much needed time-area and reduce piston-mass for the higher revs.

from a magazine from 1977 :

Pat whatever have a gif of one only problem is the pic shows a conventional looking piston. lol


Or a slightly different variation

Gets around the two diameter piston be interesting with the heat treansfer though.
Anyone What temp is the mixture after it is shunted into the hot environment of the cylinder through a hot engine.
Would there be any advantage of a dry sump like crankcase set up it could be a stroke behind it could also be manipulated in size and evacuated with a bellows type set up controlled by pneumatics.
Sorry last of the Crackpot suggestions for Ford.

[Frits Overmars]

That would explain the high reed cage and the clean-ness of the piston crown, but that would be sort of a uniflow engine, sort of cross-breeding uniflow and Schnuerle(I think this is wrong and there should be an umlaut somewhere) loop scavenging

The clean piston crown is easy to understand when you've seen Ryger fill up the kart's fuel tank, right from to the Euro95 (not even Euro98) petrol pump (gas pump to you, Smitty). No oil is added.
The man's name was Schnürle but in German it is quite acceptable to replace the umlaut with an e behind the u, so Schnuerle is fine, Senso.

[Frits Overmars]

could it be Ryger finaly got an almost 40 year old idea working well tnx to better materials ?
but as the cylinder clearly has transfers, they just might have added this TVPS, it would certainly give some much needed time-area and reduce piston-mass for the higher revs.
from a magazine from 1977:

You made my day, Jan; you fell for it 38 years after the fact. That magazine was MOTO 73, of which I was the technical editor (and test rider, and photographer, and translator, and I also made the coffee occasionally, but somehow we managed to become the biggest motorcycle magazine in the Netherlands and Belgium).
The TVPS (Top Valve Piston System) was our 1977 April Fool's joke!

[Frits Overmars]

Cutting the piston skirt short on the Ex side has been done. It was used to win a Jetski world title in stock class on a big twin with a common pipe. It played hell with the jetting, but once we got the pumper carbs reset it made a shit load more power from the reverse pulse coming back from the 180* cylinder finding its way down the paired header and adding compression to the exposed case of the piston sitting at TDC.
I know nothing about any of this as its illegal as hell, but was never found in tech.

How can it be illegal when a piece of piston skirt goes missing unintentionally, and somehow the engine keeps running ?
By the way, did you know that some Yamaha twins (the RD400 if I remember correctly) were sold with such a TDC exhaust-to-crankcase connection for a while?

[Frits Overmars]

BTW 2: here is a patent about using the exhaust pulse from one cylinder of a 180°-twin to improve the filling of its neighbour.

[husaberg]

BTW 2: here is a patent about using the exhaust pulse from one cylinder of a 180°-twin to improve the filling of its neighbour.

No idea what it did or how it worked but it linked both in maybe a Vtac kind of way?

KVSS: stands for Kawasaki valve synchronization system
Exhaust device mounted on the Kawasaki KR250S (1985 years).
Small hole that connects the two exhaust muffler (orifice) is a system that opens and closes by the engine rotation speed.
By utilizing a pressure wave of the muffler next supplement the low-speed torque.

Although a tandem the Kr1 was a 180 degree set up.

How can it be illegal when a piece of piston skirt goes missing unintentionally, and somehow the engine keeps running ?
By the way, did you know that some Yamaha twins (the RD400 if I remember correctly) were sold with such a TDC exhaust-to-crankcase connection for a while?

The old Rotax exhaust pressure driven EX valve springs to mind too

If its the one I was thinking of the Daytona Special I seem to remember it have valves in the exhausts to close them shut on over run to lower emissions maybe controlled by vacuum?

Several significant changes have been made for 1979, some dictated by clean-air requirements, others not. The RD400F is fitted with a butterfly valve at each exhaust manifold to decrease emissions during the deceleration mode of EPA testing. By reducing emissions in that one mode, the overall score is lowered enough for the bike to pass the overall test, yet performance is not significantly compromised.

The valves are controlled by engine vacuum and throttle opening. When the carburetor slides are raised less than 3.3mm, a valve located at the carburetor linkage remains closed. With that control valve closed, vacuum from the intake manifolds opens a dashpot located underneath the carburetors, behind the cylinders. That dashpot pulls butterfly valves closed via an adjustable rod linkage which runs underneath and between the cylinders to the exhaust valve assembly.

When the carburetor slides are raised more than 3.3min, the control valve opens a line leading from the airbox, dashpot vacuum drops, and the butterfly valves spring open. The valves are either open (under most conditions) or closed (under deceleration and very small throttle openings) and do not hold at any position m between. When the control valve is open, the line from the airbox constitutes a coitrolled air leak, which is compensated for in carburetor jetting. (A one-way valve in the intake manifold vacuum lines prevents any reversal in the emissions system air flow.)

The valves are effective because a twostroke is less efficient with the throttle closed, especially when decelerating. The rich air/fuel mixture tends to run right through the cylinders and out the exhaust without complete combustion, and the lack of compression braking effect allows a decelerating two-stroke to coast with the throttle shut for relatively long distances. That adds up to lots of emissions during deceleration. The butterfly valves work on a sort of potato-up-the-exhaust-pipe principle - with the exhaust plugged, emissions aren't a problem. In actual fact, it isn't that dramatic. When open, the exhaust manifolds are 1-7/16 in. diameter, for a combined exhaust area of 3.25 sq. in., not counting the obstruction caused by the open butterfly valves. With the valves closed, exhaust exits through two quarter-inch holes in each valve, for a combined exhaust area of 0.2 sq. in. It isn't a case of total blockage, but it gets the job done.

http://www.oocities.org/bezean/CWArticle.html

[Frits Overmars]

Cutting the piston skirt short on the Ex side has been done. It was used to win a Jetski world title in stock class on a big twin with a common pipe. It played hell with the jetting, but once we got the pumper carbs reset it made a shit load more power from the reverse pulse coming back from the 180* cylinder finding its way down the paired header and adding compression to the exposed case of the piston sitting at TDC.

Wait a minute... That same reverse pulse would arrive at the exhaust port of the cylinder where it originated from, at BDC, right? So that would be a suction pulse.
How do you persuade a suction pulse to add compression to the exposed case of the piston sitting at TDC ?

[husaberg]

Wait a minute... That same reverse pulse would arrive at the exhaust port of the cylinder where it originated from, at BDC, right? So that would be a suction pulse.
How do you persuade a suction pulse to add compression to the exposed case of the piston sitting at TDC ?

Diaphragm ie Pumper carbs do that every day don't they? In a round about kind of way given some time to relax
Attachment 312546

then again.
http://www.aficionadosalamecanica.ne...bo/comprex.jpg

Frits could there be advantages in skip stroking ie skiping a fuel and or ignition cycle if it was done in a controlled manner for total cylinder filling.



http://papers.sae.org/922310/

[ken seeber]

Well Neil you have fallen right into the trap.
There is no trick new engine in reality, the buggers are using the 2T community to slowly extract a hundred dumb ideas
from that may in fact end up as a couple of good ideas,that can then be patented.
The next step is to then sell this newly patented idea to GM or sumsuch for a trillion dollars and retire to the Bahamas
where Frits then joins them in secret a few months later with his own suitcase of USD.
Very slick, but now we are onto them, so no more smartarse ideas on here thank you.

Wob's certainly got a point. However, one thing is for sure and that is if Neil or anyone spreads their legs with a trick idea, then it is automatically in the public domain. This means it cannot be patentad. However, sometimes it is not the actual basic idea that draws in the dollars, but how that idea is implemented.
So, it might be wise if you think you have a good idea to either keep it to yourself, or trusted associates, develop it a bit and if it's worthwhile than do the provisional, and then, the patent thing. But, if you don't really care about going off to the Bahamas, then by all means let it all out.

Either way, if the end result is that the 2 stroke or 2T (gotta get used to saying that) can take a step forward, then many of us (not all though) will be happy.

[peewee]

By the way, did you know that some Yamaha twins (the RD400 if I remember correctly) were sold with such a TDC exhaust-to-crankcase connection for a while?

as were some ktms but most people dont know this because they didnt bother to look

[Flettner]

Wob's certainly got a point. However, one thing is for sure and that is if Neil or anyone spreads their legs with a trick idea, then it is automatically in the public domain. This means it cannot be patentad. However, sometimes it is not the actual basic idea that draws in the dollars, but how that idea is implemented.
So, it might be wise if you think you have a good idea to either keep it to yourself, or trusted associates, develop it a bit and if it's worthwhile than do the provisional, and then, the patent thing. But, if you don't really care about going off to the Bahamas, then by all means let it all out.

Either way, if the end result is that the 2 stroke or 2T (gotta get used to saying that) can take a step forward, then many of us (not all though) will be happy.

Yes, I've long since realised that I've got no idea so I'm happy to just blurt it out. You never know something may come of all this.