3 Ninjas was this movie in 1992 three Caucasian brothers who inexplicably had the Chinese Prof. Howard Birack (Victor Wong) as a grandfather. It was a wuxia comedy, they were taught to be ninjas and kicked butt. My cousin and nephew and I watched it like crazy, over and over. My cousin was Colt, my nephew was Rocky and i was Tum-Tum and that was upside down because Rocky was the oldest and I am the oldest and my nephew is the youngest. This was before our Power Rangers obsession and during the Ninja Turtles one. Mine never ended.
The second movie 3 Ninjas Kick Back (1994) but the third to be filmed. They traveled to Japan to save their grandfather, and met a girl ninja. I liked the aspect of Japanese culture in this movie and seeing a modern Tokyo. Also it had the cute Sean Fox, who I saw previously in an ep of "Full House." He took over the roll as Rocky. Tum Tum was also replaced, Max Elliott Slade (Colt) was the only to return. Michael Treanor didn't like Hollywood so chose not to continue.
3 Ninjas Knuckle Up was released in 1995 while being shot before 3 Ninjas Kick Back. This the only movie to be rated PG-13 and to have the original trio back. The reason why this was late to release has not be divulged. It was probably shot in 1993. I did not see this one.
3 Ninjas: High Noon at Mega Mountain famously starred Jim Varney and Hulk Hogan. It was also Victor Wong's last movie. Michael O' Laskey II played Colt but played a young Rocky in Mighty Morphin Power Rangers. I did not see this one either. This one came out in 1998, two years after Laskey did PR.