The Future of 2 Strokes Once And For All

[CaptainObvious]

Micahdawg (did I really just type "dawg"),

Not withstanding XRpredator's posts, you have managed to miss the entire point of this thread. A 250 four-stroke is NOT in the same class as a 250 two-stroke. The two-stroke makes almost (back off Rich and mtk, you have to allow me some editorial license for simplification) twice the power (or BMEP, happy guys ;) ) then a four-stroke of similar displacement.

It’s no wonder that the two-stroke repeatedly beat the four-stroke in your unscientific experiment.

Please re-read the thread, grasp its basic concepts, and feel free to rejoin the conversation.

 

[Micahdawg]

hello captain obvious.

I thought the point of this topic was to speculate as to how long the 2 stroke would continue to be produced. In that sense, we are both way off the mark. Since we are all off topic though, I did feel somewhat motivated to stick up for the two stroke to the repeated statements of:

"two strokes suck"
"two strokes still suck"
"...discover the superiority of the thumper"

How about I'll stop defending the two stroke, when some four stroke fans quit using, "they are not in the same class" as a crutch for their motor's inefficiencies. You can say a 250 2s and a 250F aren't in the same AMA ruled class all you want...but in the end most of us don't race and do a lot of riding without rule books. In which case it gets old hearing the same flawed argument.

Micah

 

[john3_16]

Go ahead and get behind the EPA with the 4 stroke movement and buy all the 4stokes you want, but don't complain when it costs $7,600 for a dirtbike and the repair bills start skyrocketing...

I don't care what class is what....A 250cc motorcycle is a 250cc motorcycle...I can't believe how many people think 1+1=3....

Wake up.....There is no 4 stroke advantage...It's called a rule advantage!

250cc 4 stroke = 34 hp
250cc 2 stroke = 47hp (CR or KTM)

A 250cc 4 stroke is not a 125cc motorcycle. The ama has simply bent the rules to lure people into a rule advantage

Two strokes are simply more powerful, easier to work on, lighter, less expensive to maintain, and more reliable (unless you're riding an XR).

 

[pace]

The National Basketball Association today anounced a rule addition that will go into effect for the 2006 season. Rule 3, section V can be summarized as follows: All players of African American descent shall have a maximum height of 5ft. All caucasian players shall have a maximum height of 7ft 6 inches. The NBA has determined that such a rule will allow white players to maintain parity with more powerful black players, and will stimulate the draft for up and coming white basketball prospects.

Unfortunately this is not much different from what we see with the current AMA MX/SX displacement rules. But let's not pretend that this is peculiar to our sport. Take superbikes, for example where the V-twins have a 33% displacement advantage over the four cylinder machines, or NHRA rules where different minimum weight limits apply according to powertrain configuration. It is quite common in fact, for sanctioning bodies to impose rules that favor inferior equipment configurations to enable them to compete in classes that they would not otherwise be able to.

Clearly then, the reason that so many folks are crying foul over the two-stroke/four-stroke arrangement is the 100% displacement advantage that has all but rendered the 125 obsolete in its own class. And then we have to listen to this horsecrap about how the lighter, simpler, more powerful two-stroke sucks in comparison to the four.

 

[Lissa]

Michdawg, john and Pace; Thank you for clearing the air on our side of the fence. Some people just like to toss cr@p in the tank and watch us get pissed. Oh yea, XR's only self-destruct when raced.

 

[CaptainObvious]

I never said 1+1=3. In fact, here is some math I will stand behind:

2-stroke - for each 360 degree rotation of the crank there is one power stroke
4-stroke - for each 720 degree rotation of the crank there is one power stroke

There is the simple definition that places a 4S 250 and a 2S 125 in the same class. You don't hear the four-stroke guys complaining that 2-strokes are "allowed" more power strokes per rotation of the crank, do you? Of course not, that's absurd.

By the way, check the info below my name...what do you see? Yes, I own both a 2-stroke 125 and a 4-stroke 250. I like 'em both. But I can see that the AMA rule is (almost) fair. Yes, the 4S has a power advantage, but the 2S has a clear weight advantage. Once again, do you hear the 4S guys...er riders (sorry Lissa) complaining about that? Nooooo. For reasons I don't understand, some two-stroke riders have a chip on their shoulders and are real whiners. All other two-stroke riders ride like the wind, and it matters little what they are on, they are fast.

Heck, there are kids on 85's that make me look like I'm riding backwards. Do I complain about that? Well, not to anyones face...

And Pred, that KTM 4-stroke is a diesel pig. Come to Dirtweek 05 and prove me wrong.

 

[YZ165]

And Pred, that KTM 4-stroke is a diesel pig. Come to Dirtweek 05 and prove me wrong.

:laugh:

 

[Chili]

Junk if you feel the 2 stroke 125 is on almost the same footing as the 4 stroke 250 for racing you need to pay more attention. Check out this thread if you need more confirmation http://www.dirtrider.net/forums3/showthread.php?t=111161 Marcus supplies some dynos that show an 05 RMZ making almost double the horsepower at 7k than his modded 04 125. Yes the 125 makes the same peak power but it does it over a rpm spread of a few hundred versus a few thousand rpm.

 

[CaptainObvious]

Marcus supplies some dynos that show an 05 RMZ making almost double the horsepower at 7k than his modded 04 125. Yes the 125 makes the same peak power but it does it over a rpm spread of a few hundred versus a few thousand rpm.

But that's more an issue of riding technique. To be competitive a two-stroke MUST be ridden on the pipe. If a racer doesn't like riding in such a narrow rpm range, the racer more than likely will prefer the four-stroke.

That’s what I enjoy about the four-strokes. It really doesn’t matter what gear you are in, the power is always there. In fact, Gomer was showing me at DW that it is easier to jump a four-stroke a gear up with little throttle. That is just the opposite the technique on a two-stroke.

Most riders like to talk about peak horsepower numbers, but the truth is, we (by we I mean us mere mortals, not the top racers) actually ride the torque curve.

That is the four-stroke advantage.

 

[steve125]

I agree Chili, the 125 class as far as the 2 stroke goes doesn't even exist anymore. The 125 is clearly out powered by the fourstrokes. To think the lighter weight of the 125 vs the heavier weight and the extra crankshaft revolution of the 4 stroke should even things up is a joke. :fft: Those 4 strokes rev up just fine and make "BIG" power. Then add the "unleaded" race fuel to the mix and the 125 takes another step back.

Racers aren't stupid(most anyway :) ), when they see a clear advantage they buy into it. The 125 2 stroke is history on the race track, unless a rule change comes about.

I think they(AMA) will just re-name the class and be done. :|

 

[bedell99]

They can't go back and rewrite the rule and change the displacement of the 250F's. If I was the AMA I would allow an 80 over rule in the 125 class bumping up the displacement to 133 and drop the weight limit to 186. I think this would bring the bikes back to par with the four strokes. Thats the only thing they can do. For all the people who think that a 125 is on the same par as 250F are crazy.

Erik

 

[Micahdawg]

That pretty much sums it up.

 

[mtk]

But that's more an issue of riding technique.

No, it isn't. It's a clear advantage to the four-strokes. All the riding technique in the world doesn't make up for a deck stacked squarely against you.

Yeah, I'd prefer a bike with a crapload more power too. It has nothing to do with riding technique.

 

[XRpredator]

and I'm crazy. And I will continue to hammer the suckitude of 2 strokes, cuz I'm also ornery.

and ol Vic aint' so much a pig, Junk. The ol' XR was a pig. Hell, it's name was Earth Pig for that matter.

I think peeps just like two strokes because their high pitched whine is drowned out by the high pitched whine of the engine :nener:

 

[Micahdawg]

MTK...you'll have to forgive captain obvious for sometimes overlooking the....um....obvious.

Micah

 

[mtk]

He's "Captain," not "Master of the...." ;)

 

[dirt bike dave]

As shown on Marcus' dyno charts, a strong running, full race 125 might make 30+ hp over a 2,500 rpm range (and most 125's will not run that strong, perhaps making 30+ hp over a 1,500 rpm range).

The 250 four strokes are making 30+ hp over a 5,000+ rpm range.

That's a huge competitive advantage. IF the AMA and the manufacturers had any interest in preserving 125cc two strokes at the pro level, the rules would have to be changed. Not going to happen.

Adios to the 125cc two stroke - it was nice knowing you.

 

[Kyleb15]

Do any of you riders know when they will come out with the aluminum frame 250F's. I think that will attract more FS buyers. I would sure like to have one, but money is facter for me.

 

[XRpredator]

Do any of you riders know when they will come out with the aluminum frame 250F's. I think that will attract more FS buyers. I would sure like to have one, but money is facter for me.

Honda makes one, or so I hear . . . :)

 

[CaptainObvious]

MTK...you'll have to forgive captain obvious for sometimes overlooking the....um....obvious

He's "Captain," not "Master of the"

Pred, time to start-up the whambulance. Does it come with a queen size bed?

 

[john3_16]

I never said 1+1=3. In fact, here is some math I will stand behind:




By the way, check the info below my name...what do you see? Yes, I own both a 2-stroke 125 and a 4-stroke 250. I like 'em both. But I can see that the AMA rule is (almost) fair. Yes, the 4S has a power advantage, but the 2S has a clear weight advantage. Once again, do you hear the 4S guys...er riders (sorry Lissa) complaining about that? Nooooo. For reasons I don't understand, some two-stroke riders have a chip on their shoulders and are real whiners. All other two-stroke riders ride like the wind, and it matters little what they are on, they are fast.

Heck, there are kids on 85's that make me look like I'm riding backwards. Do I complain about that? Well, not to anyones face...

And Pred, that KTM 4-stroke is a diesel pig. Come to Dirtweek 05 and prove me wrong.

A powerstroke advantage ? Well, figure out a way to bring the 4 strokes down and the premix out and I'm sure we'll even up the score.

The reason why there's whining is because there is a goal by the EPA to totally eliminate 2 strokes..The AMA is cooperating by giving the 4 stroke a huge cc advantage to lure riders and manufacturers to accomplish their (the EPA) goal..Now costs are skyrocketing and soon we won't have a choice between a 4 and a 2 stroke...

We all know where this path goes in what is called "progress"....It won't be long till we'll have some really powerful electric MX bikes that costs $10,000 plus and weigh 400lbs...

 

[Lissa]

I'm with you Lou on what you said...
I'm not sure how many of you will remember the start of the current 4str craze. Prior to the YZF400, from time to time a off-beat manfacture or custom builder would create a really cool custom 4str MXer that would make it into he mags. No one thought differently because no one could afford it or would consider buying such a obscure bike. Everything else 4str at the time was foo-foo trail bikes. Then came the '96 XR400. This big air-cooled behemoth grew to be quite popular for all kinds of task, including MX. Not that this bike was comparable to any 2str's of that time but it had a place in the 4str class along side the high dollar Husabergs and others. Yamaha saw this and went ahead and did what no other manufacture saw coming. They took the Honda idea one step further and built a 4str not for trails, but for actual MX out the box. Was it as competitive as the current crop of 2str, maybe not. It definetly had a weight disadvantage but the potential and idea was there for all to follow. Yamaha devolped the YZF as a choice, something different to offer on the showroom floor. Since it was being offered by a major manufacture with a strong dealer network, customers wouldn't be scared of purchasing the new bike. If Yamaha had never hatched the production 4str MXer, things might be quite different right now. Who knows how long it would have taken the other manufactures to even consider changing their tune. At that time there was no threat of emissions regulations and for most of us now there still aren't any. If most people actually read the rule proposal they would understand that 2str's for most applications will not be affected. Instead of the so called .49 total of emmissions we create as a whole (2str and 4str {epa}, another case of picking on the small and quiet) the new wave of 4str machines create enough noise emmissions to piss every neighbor off in a one mile radius. As long as we keep purchasing 2str's they will not go anywhere. As a clue to our local purchasing habits, I've sold four times as many 2str compared to 4str this year. Go figure.

This whole 4str development started long before the EPA even got the wise idea to try passing emissions on production off-road bikes. What personally aggravates me about this is the fact that off-road bikes are such a unbelievably small pollutant source (0.49 total !, I know this because I was involved in a EPA survey {why'd they wanna talk to me is beyond me} at our shop and I asked the guy what the big damn deal was. He told me 'they' look at the total picture {all pollution emitters} and try to reduce all of the sources). I just think it's a huge waste of time to go after OHV's when almost all of the pollutants are from big industry and automobiles. The people these laws will affect are those that ride on state land, not the private riding parks (or closed course). Race bikes are race bikes, it is gonna stay that way. If the manufactures were smart they would produce easily modified modern "dual sport" bikes. At this point there aren't any MXers, 2str or 4str, meeting any emissions so that argument is pointless. Their all doomed in a year to the confinements of a track unless the manufactures build otherwise.

 

[john3_16]

The emissions argument isn't pointless....The issue is that the EPA is trying cut cut emissions and public riding areas are being shut left and right and the "cleaner burning" 4 stroke is being pushed....The AMA and the manufacturers are going right along with the EPA....Trust me, the EPA does not like 2 stroke vehicles, in their mind it's a bigger polluter (we're not talking just CO2 alone here). The idea that the current 4 stroke craze isn't related to an EPA push toward an agenda would prove to be a fatal mistake for offroad riding.

Yes the manufacturers are still making the 2 stroke but they are feeling the squeeze...The goal (EPA) is to phase them out completely...It's a gradual conditioning process and it will bottleneck eventually with offroad riding being illegal.

You want EPA friendly dirtbikes ? Well, then you can expect costs to skyrocket and performance to dramatically drop....You've got to do alot of unplugging to get a dual sport to really run good...Unless you dramatically increase the displacement and we know where that one has gone.


The same thing happened in Moto GP road racing...In Moto GP the manufacturers are let loose to produce a full on works bike in the 500cc class and the only rules are that the bikes are limited to 500cc and the bike had to be a non production unit....They were all racing 500cc 2 strokes up until a few years ago there was a rule change and 1000cc 4 strokes were allowed to compete.

Do people actually believe that the manufacturers wanted to do that so there would be a consumer option available ? 2 strokes are lighter, faster, and much more cost effective for the manufacturer and the consumer...Remember, they can't race a bike in Moto GP that is sold on the production floor...It's a rule...They can use it as a testing ground for future production technology but that's not the reason there was a rule change.

It's not the manufacturers fault either...They are forced to comply with governmental regulations...

The AMA rule change wasn't made because Yamaha came out with a competitive 4 stroke that happened to be double the displacement...The AMA knows that it would be virtually impossible to build a 250cc 4 stroke that is competitive with a 250cc 2 stroke...The AMA had to change the rule because the manufacturers are forced to do these things by the EPA or get heavy fines...Yamaha built the bike because they know perfectly well what's coming down the line...Don't think for a minute that the manufacturers aren't well informed about the penalties of non compliance with environmental regulations...

 

[Lissa]

I know that, of course that the manufactures are going to build in compliance of the EPA regulations. All I said was that initially when Yamaha introduced the YZF400 there was no intention of regulating dirtbikes yet. It wasn't at that point a 'writing on the wall' ordeal since the rule(s) was out there already for years. It just so happened when the EPA started to draft up new emission regulations on motorcycles (on/off) since it hadn't changed in twenty years, they included OHV's for the first time. The AMA fought to keep them from imposing ridiculous contraptions on our bikes to meet those emissions. Instead of a across the board limit they divided up the rules by displacement and intended use. I'm still disappointed with the AMA's job on the matter, but it could've been alot worse. I am familiar with what happened in Moto GP.

 

[mtk]

MotoGP switched to 4-strokes at the manufacturers request since the knowledge they gained with the 500s is useless since there are no production two-stroke streetbikes. Moreover, development of the 500s had stopped years ago. The change had absolutely nothing to do with emissions regulations. It had everything to do with the manufacturers not wanting to pour millions of dollars into obsolete technology (from a production standpoint).

The EPA is simply looking for a reason to justify it's existence. Auto emissions are so low right now that it is on the limits of our ability to measure them. They tout that LEVs have "half the emissions" but in reality we're talking 2 ppm versus 4 ppm and we have trouble measuring down to 2ppm in the first place (note that the numbers are made up; the concept is not). Dirt bike emissions, like barbeque grills (I'm not making that one up either) are owned by private citizens. Unlike corporations, we don't have the money to hire lawyers and lobbyists to fight these regulations. We've already cleaned up the major sources of pollution and there really is little need for more. But you can't justify ever-increasing budgets without some new boogeyman to go after.

The whole thing is a complete circle-jerk. One airplane taking off pumps out WAY more hydrocarbon emissions than all the offroad vehicles in America. OK, maybe not one airliner, but I'm pretty confident that a few hours of activity at O'Hare airport will cover it quite nicely. But since the FAA would tell the EPA to piss off if they stuck their nose into air travel (the FAA has a problem with planes falling from the sky, so you don't muck with aircraft) they go after your dirt bike and your barbeque grill.

As for the AMA and the rules, I imagine it was like anything else in AMA racing; they screwed the pooch. Those folks could screw up a wet dream and do it quite frequently on the roadracing side. Why should SX/MX miss out on the fun?