alfadoctor

I did some digging about what the "lost motion assembly" does. This is a very important part to the V-tec valve assembly.

"First off an explanation
lost motion assemblies have a very simple job to do. they basically provide constant pressure to the rocker arm that the vtec lobe travels on. as for the reasons to why this is necessary i have no deffinitive answer but its fairly obvious. when you are not in vtec and the rockers are not bridged together with the locking pins the rocker arm that the vtec lobe rides on basically just sits there. without the lost motion assembly the rocker would just sink or most likely fling itself around from vibration. so this item, the lost motion assembly sits underneath of the vtec rocker arm and keeps it held up so the vtec lobe on the cam can ride on it. i would also assume that without this device in there and the rocker arm being either sunk or flinging around it would be alot harder for the pins to slide and bridge the rockers for vtec operation. i would also assume from just looking at the design that by keeping the rocker suspended and allowing the lobe to ride on it would help balance centrifical stress.

Also check this link for more information... Lost Motion Explanation