I edited the Light Tank to have the Lightcycle model, and I set the player to crouch on mount. I deleted the Light_Tank_Exhaust.cs in the lighttank folder (cycle doesnt have exhaust) and moved in the new model. I deleted the old one and changed it in .cs to have the shapename as Lightcycle.dts.
Now I start a server, select it, press Send, but nothing appears. It's selected as it in the vehicle menu, but nothing appears.
List of what I did
Delete the exaust CS file.
Replace the .dts model with the new .dts.
In the .cs main script, change the model file name to match the new dts.