Is nothing sacred to Hollywood’s exploiters? Remake “Casablanca” if you must—or bring us a new “Wizard of Oz.” Take “Citizen Kane” out of mothballs for an updating based on Rupert Murdoch. But “The Karate Kid”? What desecration!

Okay, so the 1984 “Kid” isn’t much more than a pint-sized version of “Rocky,” but it was cannily manufactured (if overly extended at 126 minutes) and the chemistry between Pat Morita and Ralph Macchio was palpable. This new version increases the running-time by twenty minutes, worsening one of the earlier film’s flaws, and changes the locale from California to China (the original duo didn’t go to Okinawa until the sequel). And the martial arts mode it involves isn’t actually karate at all, but kung fu. But “The Kung Fu Kid” wouldn’t be pre-sold, would it?

For the most part, though, this re-do by Harald Zwart isn’t awful, just unnecessary. The story remains an innocuously uplifting tale that can make bullied kids feel good about the possibility of the worm turning (however unlikely that actually is), and the new leads make an appealing pair who work well off one another. Jackie Chan is especially fun as Mr. Han, the depressed maintenance man with a secret skill to impart. As the recently-relocated Dre Parker, Jaden Smith, who’s obviously enjoying a growth spurt that’s concentrated more on height than on bulk, overdoes the brat stuff early on, when the move by him and his mother (Taraji P. Henson, coming on awfully strong) from Detroit to Beijing proves hard on him, but he grows more likable as the movie proceeds, and handles the physical side of the role perfectly well.

But Zwart and scripter Christopher Murphey too often stray from the single-mindedness that gave the original picture much of its punch. A major reason is that they want to impress the greatness of Chinese culture on us. So we get digressions on the Chinese mastery of ping-pong, for instance, or on puppet theatre, or on Chinese expertise in classical music. Often this veers into pure travelogue territory. There’s not just a school field trip to the Forbidden City but another journey by our heroes to the scenic mountain redoubt of a group of kung fu mystics, where little Dre can learn the secret of inner strength. Oddest of all are the shots of the duo doing their exercise routines on the Great Wall. Sure, they’re lovely, but why would they travel there to run and stretch?

The rationale behind the repeated thrashings Dre gets at the hands of young bully Cheng (Wang Zhenwei)—some of them needlessly prolonged and brutal, by the way—also gets unnecessary amplification by another importation from “The Karate Kid 2”—the addition of a puppy-love subplot between Dre and aspiring violinist Meiying (Han Wenwen), which stokes the jealous Cheng’s ire. This material may cause the young boys at whom the picture’s aimed to become fidgety.

Still, they’ll enjoy the action set-pieces, especially when Chan is involved (his big fight, when he saves Dre from Cheng and his minions, is far more protracted than it was with Morita in the earlier picture, and filled with the jocular touches he’s famous for). The final tournament sequence is ridiculously gaudy—the big neon scoreboards, complete with portraits of the competitors, are an especially overbearing touch. But the actual fight material is effectively handled, although the prolonging of the decision about whether Dre will continue to the finals after his leg’s injured is a bit much (and one might miss the postscript pitting the two “masters” against one another—it’s omitted here).

It remains to note that the movie benefits from the widescreen cinematography by Roger Pratt, who luxuriates in the locations (especially when he gets to shoot large regimented masses of people doing exercises, or the mountaintop vistas and Great Wall sequences). And all the behind-the-scenes tasks are expertly handled (though James Horner’s score is undistinguished).

But while this “Kid” should be engaging enough for those coming to the tale for the first time, it certainly won’t efface memories of the original for those who’ve seen it.