CR500 and KX500 = sick horsepower. I know I've ridden both. Talk about a rocket on 2 wheels. Well more like a unicycle if you ask me. The front end is hardly ever on the ground.

 

[img]i/expressions/face-icon-small-happy.gif[/img] lol thats true!!!you have to have good balance and a very disciplined throttle hand!!

 

killerkx327 made a very good point and what he said is 100% correct. 4 strokes just cant match cc to cc with 2 strokes. I own a GSXR 1000 and a Thunder 1000 snowmobile. Getting off one and on the other is 2 totally different worlds. 4 strokes take more work and $$$$ to get power and tourqe improvements to equal out to a lesser CC 2 stroke motor.

 

Two stroke vs four stroke, the two stroke makes a power stroke every time the piston goes up, but the four stroke makes the power every other stroke. The oil could be taken out of the fuel if you used used a sump for oiling the bottom end and the cylnder walls still using the piston to do the intake and exaust timing AND adding a postive displacement supercharger such as a screw or a roots type supercharger to blow the fuel air mixture into the clynder. emission problems come in when the piston has opened the exaust port then continues down and opens the intake port the blower will have to blow some unburned fuel through the ekaust port while it is open. The two cycle diesels used exaust ports in the clynder walls but also used overhead valves (some used four valves) for the intake with the associated drivetrain, back to the four stroke weight and complexity. And since the fuel was direct injected at the top of the compression stroke, there wasn't the problem of blowing unburnt fuel out of the exaust.
Two stroke appears simpler to produce and lighter for the power produced and able to turn higher rpm's (no valves to open and close)power stroke on each revloution, higher rpm possible only moving parts are the crank and the supercharger and the only recripcating part is the piston and rod.
would 20,000+ rpm interest anyone on a bike with the motor between their legs? How about a broke rod?
My .02 worth anyway

 

Guys Evinrude (Bombardier owns the company) already makes a 2-stroke outboard motor that use direct injection (no not EFI) that makes fewer emissions than a 4-stroke, according to their website. My brother-inlaw bought this motor last week along with a boat. Apparently these motors make some serious HP. Check out www.evinrude.com

 

I am also not an expert on the subject, but!!! There already exists a two stroke with a seperatee crake case in the engine world. It's any diesel. All diesels are two strokes, but they use fuel injection for fuel delivery. I'm sure there are engineers smart enough to develope an enging with the power on a two stroke as we know and love it, but mix it with the mechanics of a modern diesel. We'll see it someday.

 

The oil is not the main problem. There are plenty of clean burning two stroke oils today. The problem is that a two stroke does not have physical valves that open and close to prevent raw fuel from exiting out the exhaust. As a matter of fact, a good pipe does have raw intake gasses exiting into it. The pulse wave then rams those gasses back into the exhaust port before the piston covers it. Some raw fuel still makes it way out. With direct injection, the fuel is injected into the cylinder after the ports are covered by the piston. The motor can still have a tuned pipe because it is just air going into the pipe. The oil is injected into the crankcase. Much less oil is probably needed since the fuel is not constantly washing it away.