There were frame builders like Antig, Ansel, Elstar. I even saw a 500 Triumph in one once, I can't remember if it was competitive at the event, probably not. The old factory motocrossers used to spin up rather than find traction compared to singles.
Do you do Facebook? Nice page for photos and detail shots:
https://www.facebook.com/groups/530272923674162/photos/
Google page of vintage grass track:
https://www.google.co.uk/search?q=v...nKHlAhVLblAKHdwNCGcQ_AUIEigB&biw=1366&bih=595
Douglas DT5 (Dirt Track) racer. The knee hook was from the old leg trailing system, it stopped riders being dragged off the back when digging the left toe in to help the slide.
Do you do Facebook? Nice page for photos and detail shots:
https://www.facebook.com/groups/530272923674162/photos/
Google page of vintage grass track:
https://www.google.co.uk/search?q=v...nKHlAhVLblAKHdwNCGcQ_AUIEigB&biw=1366&bih=595
Douglas DT5 (Dirt Track) racer. The knee hook was from the old leg trailing system, it stopped riders being dragged off the back when digging the left toe in to help the slide.