How does an exhaust power valve work?
An exhaust power valve automatically varies exhaust-port size based on conditions. When starting from a dead stop, it restricts port size, increasing air velocity and throttle response. As engine rpm climbs, the valve opens to provide better high-rpm power. Older exhaust power valves were strictly mechanical.
What does the exhaust valve do on a motorcycle?
The valves allow the intake mixture to enter the combustion chamber, and the spent gasses to exit after combustion. However, the most important job valves do is to seal the combustion chamber so that the intake mixture can be compressed and ignited. That’s pretty much it.
At what temperature does the exhaust valve open?
Engine Valve Heat Treatment Description Doug Kaufman states that intake valves typically run at the range of 800–1000 °F(427–538 °C), while exhaust valves typically run at 1200–1450 °F(649–788 °C), due to the temperature difference of intake gas and exhaust.
How do I know if my butterfly valve is open or closed?
When the handle is parallel to the valve, it is closed, and when it is perpendicular to the valve, it is open. Butterfly valves are suited for use in garden irrigation, and they are also commonly used in space-restrictive applications.
What does Yamaha YPVS mean?
Yamaha Power Valve System
Yamaha Technology 1980: YPVS (Yamaha Power Valve System) Effective exhaust timing control.
What is an EXUP on a motorcycle?
EXUP or Exhaust Ultimate Powervalve, was a sort-of four-stroke version of the YPVS system Yamaha had used in their two strokes for a while. The valve in the exhaust stayed shut at low revs, increasing back pressure and boosting power.
What is EXUP system?
The EXUP system was a four-stroke power valve system, placed in the bottom-end of the exhaust’s downpipes to fool the pipe into thinking it was the best ‘length’ for both mid-range and high-rpm operation. You see, exhaust systems are a compromise.
When should the exhaust valve open?
On the power stroke, the combustion pushes the piston down in the cylinder. During this stroke, it is necessary to open the exhaust valve before the piston gets to the bottom of the cylinder. This will allow the excess pressure in the cylinder to “vent out” just before the piston reaches the bottom of the stroke.
What does YVPS mean?
Yamaha Technology 1980: YPVS (Yamaha Power Valve System) In general, fast exhaust timing means that the engine will perform well in the high-speed, high-power range, while slow timing means the engine will have good low-end torque.