You can enter in three classes:
Rigid class - Four strokes before 1969
Swing arm class - Four strokes before 1977
Minimoto class - Two or four stroke 125 cc or less
Entrance fee is ¥ 1000
I'm not sure if google translate made a mistake but I think the info says women who are under 20 years old free of charge, haha, that's funny.
Address 〒 299 - 1067 Minato Futtsu, Chiba Prefecture 1260
More info on instagram.com/grizzlycup2017/