Rocker Lockers Install vs. Cylinder Position

[Jack Klarich]

Jack, From reading about 4-stroke engines and trying to educate myself, there are four stroke positions of the cylinder. The first is the intake downward stroke with the intake valve open and the exhaust valve closed bringing in air & fuel to the cylinder. The second is the compression upward stroke where both intake/exhaust valves are fully closed at TDC burning the air/fuel created by the spark plug's spark. The third is the power downward stroke still with the intake valve closed and the exhaust valve beginning to open as the cylinder starts to reach bottom. The fourth is the exhaust upward stroke with the intake valve beginning to open and the exhaust valve fully open to expel the burnt air/gases. Then the process starts all over again.

Now, if my understanding is correct, the only time both the intake and exhaust valves are fully closed is during the compression stoke at TDC. In turn, at this time, it would be the only time that both cylinders' pushrods would be at the same height with no tension or pressure on the selected cylinder's rocker arms and springs as viewed inside the selected cylinder's support plate you are wanting to remove and install the rocker lockers. Please let me know if this sounds correct?

Also, in addition to the new Harley Breather Assembly kits and O-rings, I will be installing new rocker cover gaskets, as well, just in case one of the old rocker cover gaskets gets "dinged" or scrapped. From what I have read, the same rocker cover gasket works for both front and rear rocker covers. However, the gasket will have "front" or "rear" cylinder imprinted on the top side of the gasket to indicate its proper placement.

Thank you,

Allen S.

Yes your statements and understandings are correct. The main thing to understand about HD engines is they share a common crank shaft connection to the connecting rods. This is the direct relationship to the piston travel in both cylinders. It is pretty confusing until you see it all in motion

[keikat2]

Jack, Thank you for sending me the animation workings of the Harley engine. Observing the animation, it appears a cylinder's push rods, rocker arms, springs, and valves are all in a non-tension resting position beginning at the bottom of the cylinder's intake stroke moving upward to the compression stroke all the way down to the bottom of the power stroke. In turn, if I am correct, it appears the selected cylinder's rocker support plate could be removed at any point during this movement of the cylinder. Am I correct?

Thank you,

Allen S.

[Jack Klarich]

Jack, Thank you for sending me the animation workings of the Harley engine. Observing the animation, it appears a cylinder's push rods, rocker arms, springs, and valves are all in a non-tension resting position beginning at the bottom of the cylinder's intake stroke moving upward to the compression stroke all the way down to the bottom of the power stroke. In turn, if I am correct, it appears the selected cylinder's rocker support plate could be removed at any point during this movement of the cylinder. Am I correct?

Thank you,

Allen S.

Yes, the intake and exhaust should both be fully closed as the piston for that cylinder is ready to move up the compression stroke

[Jack Klarich]

Have a look here you can see the lift area of the cam and the base where the valve closes