diff --git a/src/mame/drivers/gaelco2.cpp b/src/mame/drivers/gaelco2.cpp
index 24b710e1e30..be473fff0fe 100644
--- a/src/mame/drivers/gaelco2.cpp
+++ b/src/mame/drivers/gaelco2.cpp
@@ -1843,7 +1843,7 @@ MACHINE_CONFIG_START(wrally2_state::wrally2)
 	MCFG_CPU_PROGRAM_MAP(wrally2_map)
 	MCFG_CPU_VBLANK_INT_DRIVER("lscreen", gaelco2_state,  irq6_line_hold)
 
-	MCFG_DEVICE_ADD("gaelco_ds5002fp", GAELCO_DS5002FP, XTAL(34'000'000) / 4) /* 8.5MHz? (or 13MHz - 26MHz/2) - Not verified */
+	MCFG_DEVICE_ADD("gaelco_ds5002fp", GAELCO_DS5002FP, XTAL(26'000'000) / 2) /* 13 MHz */
 	MCFG_DEVICE_ADDRESS_MAP(0, mcu_hostmem_map)
 
 	MCFG_DEVICE_ADD("mainlatch", LS259, 0)