Split crossovers use two shims to form the crossover gap. Split shims smooth the bend radius at the crossover shoulder to prevent kinking of the face shims on the sharp shoulder of a single crossover shim.

Valving Logic dyno testing of an rmz250 used a split shim crossover. Deflection of the high speed stack by the interactive crossover delayed closure of the crossover to 64 in/sec.

However, the dyno was not capable of testing beyond 50 in/sec. The data provides no information on the expected damping force increase after the crossover gap closes.

High speed closure of crossover gaps and valve port flow restrictions can significantly increase high speed damping making extrapolation of dyno data beyond the test range risky.

Dyno test limit of 50 in/sec unable to quantify crossover gap closure