VERY Fast Dirtbike
This is a modification of the dirtbike in jc4, (v308_bike_trails_civillian_01) in the entity spawner.
This mod DOES include nitrous and turbo jump for the vehicle in it and the bike now reaches up to 259 kmph (I think you have to use the nitrous to get to that speed though).
Just drag and drop the dropzone folder into your jc4 directory. If you already have one just put the v308_bike_trails folder into your 01_land folder.