[Bob Johnson]

The reason for plugging the lower bypass is to make up for all of the extra fluid due to wear that is moving from one chamber to the other. A shock that is not worn will move most if not all of the fluid through the bypass holes. A worn shock will move some fluid between the rotor (wing) and the shock body. It can move under the rotor, above the rotor or even the ends of the rotor. Depending on where it is worn.

Let's do some math. The bypass holes vary but are around 0.12" in diameter. That means the cross section is 0.013 square inches. The rotor (wing) sides are 1" tall and it is 2.5" wide. There are 7" where there can be a gap for the fluid to pass through. Actually only 6" because the fluid can not pass through the shaft at the top of the rotor. Are you still with me? Now 0.013 square inches divided by 6" gives about 0.002". I am not sure what the original clearance was for the shock. I seem to remember 0.0005". Anyway wear of 0.002" around the rotor will move as much fluid as the bottom bypass hole.

I conclusion you can make up for 0.002" of wear by blocking the lower bypass hole.


If you got this far you have too much time on your hands.


Bob