Some engines, especially small engines, have compression release valves so that it's easier to turn the engine when you first start it because there is less compression in the cylinder. Examples would include the Ducati 1199, or more in my field, the Kohler CV460S.
How do they work? Diagrams and complete answers would be appreciated!
https://www.youtube.com/watch?v=Iiwvhm7NjWw
First time I have heard of this but cool.
https://www.youtube.com/watch?v=JExXHohaWqo
The weight is pulled to the center of the cam using that small spring around its pivot point. This makes the lever on the end of the weight spin that pin around creating a bump in the cam profile. This bump opens the exhaust valve allowing some of the pressure to escape during the compression stroke.
When the RPMs are high enough the centrifugal force pulls the weight away lifting the lever and spinning the pin so the flat side is in line with the back of the cam lobe.
