these are pict i have taken at a local BMX track. the jumps are too big for racing but great for bashing.
http://www.radeks.net/wp-content/plu...?album=3&pos=0
what you need is lots of dirt to make jumps, at least a small buldozer as doing it manually just with shovels would take ages
and here are pictures from a track used for mostly buggies but MT race there too thi i think they deserve more and bgger jumps
http://www.modelklubkbely.cz/galerie.html