No arguments about the effect of greenie weenies, but I'll have to disagree on comparisions based upon displacement. The difference in design make that argument moot.

When compared to a 4 stroke, a 2 stroke engine has twice the amount of power strokes during any given amount of time at the same RPM, which would naturally produce twice the amount of power. Doubling the displacement of a 4 stroke makes matters more competitive, but the added weight and power rob of camshafts and valves still put the 4 stroke at a slight disadvantage, HP wise.

Also, I don't think you can broad sword the idea that ALL pro riders would still prefer to be riding a 2 stroke. There are many of them that prefer the wider, more usable power band of a 4 stroke.

 

Just get a KX500.

... And make sure your medical coverage is up to date.

 

OK I'm fine with that. All we have to do is let the riders decide for themselves what they want to ride without giving a huge displacement advantage to one group (four strokers) over the other. If riders prefer to gravitate to the four stroke over the two then I have no problem with that. My only problem is the AMA granting a huge displacement advantage to one group over the other.

Mike

 

Efficiency

The real discussion here should be efficiency.
That's what 4 strokes have over 2 strokes.
Energy out for every liter of fuel in.
What 2 strokes have over 4 strokes is power to weight.

The reason 2 strokes are peaky in there power delivery is because to extract the most power out of them, you need to tune them to a relatively narrow rpm range.
It doesn't have to be that way and 2 strokes can be tuned to be quite mild and still remain light.

But, they still consume more fuel than an efficient 4 stroke.
So the green argument has merit.

Did you know this.
We are approaching the limits on how much energy we can extract from a given quantity of fuel from an internal combustion engine.
Fuel injection being the final straw, which is on most if not all cars, and will no doubt be on all bikes one day.
To get more power out of an engine of the same capacity, we are left with increasing RPM as the main and cheapest way to do that.
So modern 4 strokes rev like 2 strokes of old.
Light weight, well balanced engine components allow this.
More rpm means more fuel burnt which means more power out.
Nothing for nothing.
Ceramic engines never really too off.
They were supposed to be the next big leap forward by reducing the amount of energy lost as heat.

Any engine technology that is more efficient than the internal combustion engine has one major short coming.
Energy storage.
If someone works out how to store the equivalent energy of say 60 liters of petrol, in a form that weighs around 55-60kgs and can be replaced easily in about 2 minutes, job done. The internal combustion engine is dead.

But that is a ways off yet I suspect.
Can't beat fossil fuels for energy storage efficiency.

So it's a little ironic that what is a relatively inefficient way to convert potential energy into actual work, the internal combustion engine, is saved by the fact that it's fuel is a very efficient way to store potential energy.

Mmmm I need to get out more.

 

OMG I can't believe anyone ever rode one of those things. Try a cr500 against a crf450... I'd rather take my chances on a bungee jump.

Mike

PS- I have considered buying an old KX500 but I have nowhere to ride it. The bike is impossible on hare scrambles. Hello open space.

 

Neilaction-

Efficiency is one thing but nobody races anything with fuel efficiency in mind. Power to weight rules the day. I agree that we are reaching the limits of how efficient we can make the internal combustion engine. We have reached the point to where the only way to increase fuel efficiency in a vehicle is to make it lighter (less safe for all practical purposes with regards to automobiles) or stop combustion altogether (hello hybrids). There is only so much matter that you can move with a gasoline explosion because we're dealing with a finite amount of potential energy.

Mike

 

Tell me if this doesn't give you the horn.
"Yeah, baby. Yeah!"

 

We need an emoticon for when IG is talking out of his a$$.

Something like:
(|)
B
L
A
H
B
L
A
H

Did you not understand that the same rider(s) on a 250 two or four stroke on the same track turned the same lap times consistently?

Last time I checked, lap times are what it's all about.

In other words, that's why the AMA is bringing them back at the amateur level; they're competitive. Look for that to go to the pro nationals level next. I'm excited, maybe it's not too little too late to get the two stroke back in action. I say bring back the 500's and let David Bailey, Kent Howerton and Jeff Ward come out of retirement and show these wussies how it's done.

Bring back Saddleback!

Now go fix your broken muzzy.

 

But it does look HORN right?

 

Agreed.
But.
Manufacturers won't want to spend r&d on technology that won't sell.
The pinnacle of motorcycle racing. GP went from 500cc 2 strokes to 990cc and now 800cc 4 strokes.
For no other reason other than Honda, Yamaha etc wanted a return on investment.
Market for 2 strokes is almost gone.

And watch the pinnacle of car racing. F1.
There will be a big push for more efficiency from the manufacturers that will result in fuel limits and stuff like energy return braking.
That's what the future holds and they want to invest in that technology through racing.