Of course we don’t need a remake if the original film got the job done.

The Karate Kid, John G. Avildsen’s 1984 rabble-rouser, was a teenage version of the director’s own Rocky.  Ralph Macchio played a very Italian underdog from New Jersey who moves to suburban Los Angeles and is forced to deal with culture shock and blond surfer kids with mad karate skills. The Karate Kid, Harold Zwart’s spiritually-loyal remake, keeps all the primary story beats from the original while transferring the action to China and customizing the whole thing so Jaden Smith can star as a 12-year-old fish out of water and Jackie Chan can play his broken-down mentor.

On its own merits, The Karate Kid plays like a straight-forward drama blown up to epic proportions. Two years after his father died, Dre Parker (Smith) finds himself moving to China with his mother (Taraji P. Hansen), whose character is defined solely through her exasperated exhortation, “Pick up your jacket!” (Dre has the habit of dropping his jacket on the floor whenever he takes it off.) For some unexplained reason, Dre’s mother, an auto factory employee, has been transferred. Is she an executive? The highly valued assistant to an executive? A key member of a creative team? A window washer whose innovative timesaving techniques are ground breaking? The daughter of the president? Suffice it to say, the movie needs a reason to be set in China, so off we go.

It doesn’t take more than 24 hours for Dre to declare that he hates it in China, and no wonder. He doesn’t speak more than a couple of words of the language, isn’t very good at basketball, is embarrassed by his mother on the first day of school, and gets beaten up for taking a shine to a local girl. What a miserable life!

Dre continues to make googly-eyes at the young beauty, and continues to get beaten up — or threatened — by the young bullies, who have an impressive command of the martial arts, especially when it comes to smacking down Dre. He is settling into a miserable existence, until he finally decides to fight back against his tormentors. That doesn’t turn out so well, either, but, fortunately for Dre, a martial arts superstar comes to his rescue.

Mr. Han (Chan), the maintenance man in Dre’s apartment building, is a somber, quiet man. He walks with a limp and, though not unfriendly, avoids unnecessary eye contact. He dispatches Dre’s foes in an impressive display, and they have a little talk. Dre has seen that the boys have been trained at a local kung fu school and thinks that their trainer is the source of their evil disposition. Mr. Han and Dre pay a visit, and it’s confirmed when they see Master Li (Rongguang Yu, who has often sparred with and against Chan in Hong Kong films). Master Li is an imperious instructor who demands that his students show “No fear! No mercy!” To avoid a physical confrontation he knows he cannot win, Mr. Han volunteers Dre to enter a local kung fu tournament.

That requires Mr. Han to teach Dre the martial arts, which will require much putting on of his jacket and much taking off of his jacket.

Chan gives a very fine dramatic performance. Only occasional glimmers of his more clownish side shine through, as when, at the end of the battle with the bullies, he offers up his trademarked “ouch! ooch” grimace of pain. He looks at least a decade older than his 56 years, but is still mesmerizing in close-quarters handiwork. He’s still awkward in delivering his English dialogue, yet he is a surprisingly effective silent communicator, which works well in the film.

More problematic is the pacing and the decision to “go young” with the lead role. The original movie ran 126 minutes but felt shorter; the remake runs something like 144 minutes (with an extended closing credits sequence) but feels longer. It seems to take forever before Mr. Han fully enters the picture, and young Smith is not yet so engaging that he commands attention merely by his appearance. Because the age of the lead character has been made younger, we’re acutely aware that this is a little kid; we don’t really need multiple bullying sequences to establish that he’s being picked on.

At the same time, it feels odd that no overt mention is made of the death of Dre’s father. Come now, for a 12-year-old to lose his father at the age of 10 is surely even more traumatic than it would be for a mid-teenaged boy. Isn’t that part of the reason why he’d have trouble adapting to his new surroundings? Also, keeping the romantic sub-plot feels a bit icky — are we really supposed to believe in the romance? — and the avoidance of racial issues entirely is surprising. Really, not even paying lip service to the idea that Dre is an outsider, an American, and an African-American to boot?

Still in all, The Karate Kid has its heart in the right place, and provides sumptuous views of the expected Chinese landmarks, including the Forbidden City and the Great Wall. Dre learns that martial arts is not about the fighting so much as the learning and the peace-keeping, and those are good messages to send to any kid.

[The Karate Kid opens wide across the multiplex today.]