What is a rotary valve

[Jsullynz]

can some one please explain the function and how the rotary valve works????

 

[Jeffspx]

It's a large circular plate that spins via the rotary valve shaft. The rotary valve is timed to the rotary valve shaft. The rotary valve shaft is then spun by the crank. So the rotary valve is timed to a certain point on the crank and spins in correlation to the crank. Now in our motors this valve takes place of the reed valves that exist in other 2 stroke motors. It opens one of the 2 intake ports when timed correctly to the intake and exhaust stroke to allow air in and then closes to keep from blowing back during the compression and power stroke. Try searching pics. It might help put it all together. Hope this helps

 

[Dave_eng]

Think of the rotary valve as the intake valve cam on a 4 stroke car engine. It controls when the air fuel mixture gets into the cylinder far more precisely that simply using the piston moving past open ports in the cylinder wall as you would find on a low cost two stroke chain saw engine.

Hope this helps

Dave p