The desmo valve it a ducati thing is is complex and not as good as spring it is very old. A rotary valve would be bacicaly a ball with a cut out you turn it one way to open the other close or spin it. There are motors running using them as test beds but the tech is not there yet to let them seal correctly.
To me a far better soulition will come when we figure hoe to manipulat a fluid w/ electricity, add juice open the valve remove juice close it. This would give infinate valve timing making a motor that would produce max torque at every RPM it would remove the cam and all of its complexity and weight and lower the center of gravity of the motor. It would also make a top end job on a 4 stroke easier than a 2 stroke. I do not know how many year away this tech is but I reall see it as the next big step.

For now I would like to see light weight inline twins this give a power stroke every revolution so you get better throttle responce and more power for a given cc.

 

Ok.

Honda 1.7L inline 4 127hp at crank.

Rotax 0.8L triple 2 stroke 155HP At crank. Under 16psi boost from a turbo 324.9Hp. I dought 16psi of boost would do the same for the honda.

Now with SDI technology that .8L 2 stroke would be making the same emount of emmitions.

But the kicker is CVT trannys. Anyone here drive sleds. Well imagine a 2 stroke that was only allowed to be in its powerband. Thats a CVT. From start to finish only in the powerband and it never goes out. CVTs are the absoulte best tranny design for a 2 stroke becasue it goes where the engine wants it to go.

I dont think 2 strokes are dead. The technology already exsits for them to be as clean and powerfull as anyone wants them to be. Just wait till bombardier gets this DI tech made smaller and cheaper. 2 strokes will make a comeback...

 

I seem to remember reading something about Chrystler Corp. comming out with a 2 stroke engine for their cars in thenext couple years.

 

That would be real neat. All you need is one of the big 3 to do it and more will follow if the results are good. And if they were to release a car today the results would be good.

 

There have been small 2 stroke cars running in other parts of the world for a while.
I have read of a 2 stroke designe that uses a crank case w/ oil so it runs straight gas, something that will be nessisary in the future. I think it uses a chamber and ports as the piston drops it presurises the pchamber instead of the crank case the creates a vacume when rising. This would work but add weight then you need to deal w/ the raw fule getting out remember the greenies know we will mod our quads and bikes so even if the pipe is perfect from the factory for great emmisions that would mean leaving unburnt fule in the cylinder and that is not good for power so we will swap the pipe. so the next step would be to add some sort of valve again you add weight. I am not saying 2 strokes are dead or that we woun't see a clean burner in the future but look at where we are.
A 250cc dirt bike makes less hp and is more pipey(sp?) than a 450cc dirt bike the 450 weighes only 10 pounds more than a 250. Now w/ new tech in a few years it will be easy for the 450 to weigh the same as current tech 2 strokes. So lets add all of the things needed to make a 2 stroke clean and then you start w/ a 2 stroke being 10 pounds more? Most people will not spend the money for it pluss it cost way to much to build 2 bikes and spend on 2 different tech.
Now Mar has made great points a 2 stroke will always out power a 4 stroke cc for cc and in the past were always much lighter plus there is that great 2 stroke sound and hit I would love to see them survive but knowing that bean counters run the show I do not think they will.
A good thing though it the ban will not affect comp only bikes and w/ a bunch of tech out there it pluss it is cheeper to build a 2 stroke we may see a few small makers building some 2 stroke units look at gas gas or vertimeti and others like them maybe ATK? Who knows?

 

Right now your still arguing that a composite bow and arrow will be better in a few years than my Match lock rifle, maybe so but which one has more potential? why dump all your time and effort into something when another has more potential. In the end when i have a full auto electro magnetic rail gun with a smart scope and your using a hopped up bow with a smart arrow we will see who wins. ANALOGY ONLY no one is making either weapon at current time [img]i/expressions/face-icon-small-smile.gif[/img]


Maybe so but thats only because the four stroke has a giant head start. I think the two stroke has way more potental for light weight, i mean even when you start adding the parts your not adding anything a four stroke dosent already have? if you can make a four strokes valves lighter why not put light valves in the two stroke? I mean no matter what you say a 2 stroke will always have less parts even if we start adding so there is no way it could ever get heavier.

Whats really sweat is some university people designed a 1 stroke rotary engine, it has pretty much constant combustion. Now that will make some power for its weight. Also remember, smaller objects have more surface area there for dissapate heat better, so even though it would make tons of heat you could make is smaller and in turn it would dissapate it better.

 

I am not arguing a good or bad I have always like 2 strokes I am stating things from a factory view. You can not reinvent the wheel, MFG's are about money. Clean 2 stroke tech has been around for a while but you do not see it on street bikes, cars even more and more boats and snow mobils are going away from it. It is has to see a trend developing when people are leaving the fold.

 

I know people are talking about 2 strokes having torque. Which i know they do, what i was talking about was the torque of rotary engines.

 

Im not real sure but in Car and Driver when they tested a super tuner 600+hp one they said it had 300ft lbs of tourqe, which is crap, but there was no torque curve, it was flat. All the way from idle to red line torque was at about 300 ft lbs so you could drive it like it was electric, if somone would add a cvt to that >[img]i/expressions/face-icon-small-smile.gif[/img]
Also you have to consider in part the reason is the tiny displacment. 300 ft lbs of torque for a 1.3 liter is pretty good unless its a diesel. Consider that its all the way from idle and were gettin even better. Pretty much think of them as electric, whatever torque you have at idle goes all the way up and more rpms just magnifies it into HP, i guess thats where their massive horsepower comes from, they dont lose torque with rpms. My guess would be though that the 300 is when the turbo kicks in because they have little compression i think. Im sure with some time and money put into them they will get awesome. The new RENESIS engine looks sooo awesome, 250hp with no turbo, i say with as much boost as the old engine got this sucker should be close to 400 - 500hp (a guess). Stick that in a 2900 lb car....... woah...... DO NOT BUY ONE FOR YOUR KID IF YOU LIKE THEM.

Hey i forgot to mention, has anyone thought to see how much you can rev one of these suckers? Put some INDY technology in one of these suckers and you should be able to rev into the stratosphere, and if your not losing torque on the way.... hp numbers in outer space. I had a video of an older one at a car show literaly do a burn out turning so many rpms it sounded like a buz saw, he burned out for about 5 minutes then his hood flew 4 feet in the air with a puff of smoke. The more i think about them the more i want one, i think the apex seals only last like 50,000 miles though (on old RX-7s)but you get a more from the new fangled ceramic ones.

Just for run, for all us young people who have never even heard one, heres a site with videos of them: http://www.scuderiaciriani.com/rx7/movies/