From left, Jackie Chan, Ben Wang and Ralph Macchio star in “Karate Kid: Legends.”

Think back to your favorite films as a kid — or your children’s favorite films when they were kids — and you’re likely thinking of a pretty mediocre or even somewhat bad movie that, for some reason, your then-9-year-old loved even if you as an adult didn’t see the big deal.

For an entire generation of kids in the 1980s, that movie was “The Karate Kid,” a pretty standard family film from the era about a kid who learns karate from the mysterious Mr. Miyagi to defend himself from a group of bullies and eventually wins a karate championship.

While nothing particularly amazing, the movie spawned three sequels in the ’80s and ’90s, a reboot/remake in 2010 and a hit streaming series “Cobra Kai” in the 2010s, mostly fueled by nostalgia.

And now, more than 40 years after that original film, “Karate Kid: Legends” is taking that nostalgia factor even further with a legacy sequel featuring two actors none of the kids in the audience will know, but who their parents and grandparents will be more than happy to see.

When kung fu prodigy Li Fong (played by Ben Wang) relocates from Beijing to New York City with his mother (Ming-Na Wen) to attend a prestigious new school, he finds solace in a new friendship with a classmate and her father. But his newfound peace is short-lived after he attracts unwanted attention from a formidable local karate champion.

Driven by a desire to defend himself, Li embarks on a journey to enter the ultimate karate competition. Guided by the wisdom of his kung fu teacher, Mr. Han (Jackie Chan), and the legendary Karate Kid, Daniel LaRusso (Ralph Macchio), Li merges their unique styles to prepare for an epic martial arts showdown: the Five Boroughs Tournament.

Hoping to grab the attention of older audience members from minute one, the movie opens with a flashback in “The Karate Kid II,” where Mr. Miyagi, played by Pat Morita, tells then-adolescent Daniel LaRusso about the origins of karate and the relationship between the Miyagi and Han families, retroactively connecting the original series to the 2010 film which starred Chan as the teacher Mr. Han. Flash forward to modern day Beijing and we see Mr. Han teaching his current students and we’ve already been reintroduced to the two best parts of this new story.

Chan has been entertaining Western and Eastern audiences for decades, not only doing all his own stunts but infusing a sense of comedy and childish fun to what can be a very serious tradition. And now, even in his 70s, he’s still getting the biggest laughs, the coolest stunts and the best lines in the movie.

Unfortunately, while billed as a big return, Macchio’s turn as LaRusso is little more than a cameo. Sure, he shows up to help train Li in the third act, but 10 total minutes of screentime doesn’t really quite live up to a three-generation “Karate Kid” legacy older fans hoped for. And yet, both Mr. Han and LaRusso working with Li in a classic ’80s sports moving training montage is always fun to see on the big screen.

But that’s mostly the second half of the movie. The first 45 minutes or so deliver a new twist on these movies — the young Li, mostly trained in Kung Fu, teaches the owner of a pizza place in the neighborhood some Eastern techniques to prepare him for a boxing match. And the guy’s daughter and Li hit it off and quickly go from friends to more than friends, except her ex is the star pupil at a local karate dojo and— wait a minute, this is just the plot to the original 1984 “Karate Kid” movie.

But wait, there’s more! You see, Li’s mom doesn’t want him to fight anymore after Li’s older brother was killed in a kung fu-related fight and they’re both still mourning his loss. And Li also has a tutor helping him with math in New York, who also becomes his best friend.

If you’re thinking that’s way too much for one movie, you’d be right, and yet this one wraps up in little more than 90 minutes, even though there’s close to two-and-a-half hours worth of story. Even though none of the stories get the time to breathe and develop to do these characters justice, “Karate Kid: Legends” manages to make it work, as cliché and familiar as it may be.