Quantas vitórias para motos com menos de 54 pontos, equipe Yamaha, uma moto de 250cc, e antes de 1977?
CREATE TABLE table_name_90 (wins VARCHAR, year VARCHAR, class VARCHAR, points VARCHAR, team VARCHAR)
SELECT COUNT(wins) FROM table_name_90 WHERE points < 54 AND team = "yamaha" AND class = "250cc" AND year < 1977