Will two strokes come back?

[Octane250F]

Obviously you are sold on FI 2-stroke, Rhein, so theres probably no sense in even discussing this with you.
Ive been around 2-stroke snowmobiles all my life and I can tell you that at no point whatsoever is the exhaust port on a 2-stroke completely sealed off and no way do those engines burn every last molecule of fuel. Its just not going to happen.
About BRP being liars, well, Ive seen enough of their E-Tec ads to know that you cant believe anything they say. They have staked their future on 2-strokes and they will say anything to make people buy into 2-strokes.
I still think you will need an expansion chamber, because like I said, no engine burns all of the fuel. Ski-Doo snowmobiles with SDI engines still have exhaust pipes with expansion chambers.

 

[MX86]

no engine will burn every last molecule of fuel, whether it be 4 or 2. the 4 stroke will burn more then the 2 stroke yes, but even that wont burn every single molecule....

 

[just_a_rider]

The 2 banger will burn just as good as a 4t as long as all the jetting is correct from the main, pilot, needle and the float setting. If your 2 stroke is jetted right it will burn clean, if it's jetted right the exhaust temps are high enough to burn the excess oil deposits resulting in no spooge and only the startup smoke from left over oil in the engine.

 

[HubertGarfunkleIII]

im a 2 stroke guy, but I recently decided to be open minded and than this thought crossed my mind, if the 4t is just about as light as the 2t (maybe weighing about 10lbs more) and generates more power torgue etc etc. and is easier to keep in the power band and also wider and broader or whatever. than maybe it is a better bike!? the only drawback being it is more expensive to maintain. the engine is has twice the displacement, which is why it has more power. so why dont they lighten up the 2t than if its half the engine size and it weights the same as a 4t.

 

[Rhein]

no engine will burn every last molecule of fuel, whether it be 4 or 2. the 4 stroke will burn more then the 2 stroke yes, but even that wont burn every single molecule....

Again, I did not say that, read my post. At least octane250F brings up new points.

Also, I must say SDI is not the answer for the 2t's future IMHO. SDI is SEMI direct. I think that is more sloppy than the Yami HPDI engine (fully direct at the head). I can see how and why it would need an expansion chamber. Having an expansion chamber or not are the least of my worries. My worries are not being able to have the freedom of choice, that the same people who preach freedom and diversity are the same people who damper them and remove them.

I know that a DI 2t similar with a few more refinements like the Yami HPDI can be the savior of the 2t engine unless a communist takes the white house in 08'. I sure hope it is. This is coming from a person who has owned 3 4t bikes and 3 2t bikes over their lifetime. That is all my argument there.

 

[XRpredator]

the two stroke is dead. deal with it

 

[friar tuck]

http://sxweekendwindow.blogspot.com/

Wanna bet? :-D

 

[XRpredator]

hey, I was fine with 'em leaving it at 400cc for the 4-strokes. Now everyone's gonna whine when a 350 beats 'em.

 

[just_a_rider]

The pred is in denile :)

 

[XRpredator]

no, he's in Idaho

 

[19Brendan81]

I forgot to mention that the two stroke motor I mentioned at the start of this chain uses a wet sump like any 4 stroke does so there is no premixing of fuel and no oil burning. Thus it has super low emissions, due to is extremely high efficiency. There is no reason why this sort of technology cant be implemented in cars and motorcycles. I estimate the engines would weigh as much as the current DOHC 4 strokes do. And the torque values created would be out of this world.

It seems that the governments on your side of the pacific are hell bent on erradicating two strokes, and for them to survive a radical rethink is in order (such as the sort of technology I have mentioned). Fortunately our economy relies on burning and selling unclean coal so the government hasnt had the hide to point the finger at the odd bloke riding a two stroke to bring emissions down.

 

[2-Strokes 4-ever]

Now everyone's gonna whine when a 350 beats 'em.

Promise?

 

[elcamino12sec]

So am I correct in reading by 2009 the cc will be 350?, what about lites, will they remain 250?

 

[2strokerfun]

So am I correct in reading by 2009 the cc will be 350?, what about lites, will they remain 250?

The AMA has done nothing. They simply met with FIM. Don't hold your breath here as AMA decisions seem to be manufacturer-driven and it has a long history of ignoring the wishes of its rank and file members. Plus, as much as I love 2 strokes, I have to realize there is a whole lot of people out there that have spent bucks on their new four strokes and are not anxious to see things change from current rules. So, what I wish isn't necessarily the majority wishes any longer.

 

[DougRoost]

Im sorry, but there is no engine that burns every last drop of fuel. Also, there is no way a 2-stroke can completely seal the exhaust port because the piston and rings dont give you a perfect seal.
If you know anything about engines, Im sure you realize that the piston slaps back and forth as it moves up and down in the cylinder and you are bound to get leaks.

Piston ring sealing and piston slap is of course true for any piston engine, being it 2T, 4T, or diesel. In fact, it's up to the oil ring to apply and scrape the oil film off the cylinders in a 4T engine, as anyone who's ever had a engine with worn rings and the resulting excessive blow-by is well aware of.

As a long-time car hotrodder, I can also tell you that a key design point for performance 4T camshafts is overlap and duration. This is how many degrees of crankshaft rotation that the intake and exhaust valves are both held open. When combined with a tuned header, it's the exact same idea of a 2T with expansion chamber adding a supercharging effect by using the exhaust pulses to further scavenge the cylinder and draw in additional air-fuel charge via the intake valve. In the current crop of racing 4T dirtbikes, you have this camshaft design coupled with the very small skirted pistons, so they, too, pollute.

The other engine design we haven't talked about is the rotary or Wankel. I used to have an RX-7 and it's a great, smooth engine. The owner's manual actually warned you to check the oil level often since if you're not using oil there is a problem. This is because they had a pump to spray a fine mist of oil on the combustion chamber walls. This obviously affected emissions but it illustrates again that all these mechanical engines require lubrication where metal is in contact with metal.

 

[rmc_olderthandirt]

http://www.evinrude.com/en-CA/E-Tec/E-TEC.Advantage/Cleaner.Quieter.htm


Please people share common courtesy and post relevant and recent FACTS, not opinions, if you are trying to make an argument.
Thanks!

You quoted me, then quoted an engin's manufacturers claim which basically supported what I said. Was there a point to that?

The direct injection systems solve the unburnt fuel problem. There is still an issue with the oil.

Rod

 

[Rhein]

There is hope after all!
http://sxweekendwindow.blogspot.com/

 

[19Brendan81]

Dude that is GREAT news!!!!

 

[HubertGarfunkleIII]

as long as the new and improved super 2 stroke comes around by 2010 ill be happy!

 

[KX'er]

After a ride in the woods this weekend, most of the bikes out there were 2t's.

 

[Racerboy]

Thats good for 2-strokes, one thing that makes more sense to me is too just choke up the 450s sound levels to where they would be similar in power to these loud 350s that might be coming. Then your 2-strokes are back in the game and you address the noise issue.

 

[KX'er]

I'm pretty sure my 2 stroke is as loud or louder than most 450's out there...