If I can get away with saying this with a straight face, “The Fast and the Furious: Tokyo Drift” is two thirds of a great B-movie Western. This third entry in the popular series of cars and babes introduces new characters (a hard-boiled expatriate high school student forced to live in Japan), different streets (the neon lit highways of Tokyo) and a new style of driving (drifting, a strangely intoxicating blend of screeching tires, speeding vehicles and heart-stopping hairpin turns). In most respects it’s the best film in the series, and while that’s not really saying much this sequel is still giddily entertaining in a ludicrous check-your-brain-at-the-door sort of way that’s borderline embarrassing.

Unfortunately, after a bang-up opening 90 or so minutes director Justin Lin (more than making up for “Annapolis” but still a long way from “Better Luck Tomorrow”) up and blows it at the climax, the epic race closing things out so silly and unspectacular it’s actually rather disappointing. While Chris Morgan’s (“Cellular”) screenplay isn’t going to win any awards, it’s still a model of white hat-black hat simplicity that’s incredibly charming. But Lin wastes it, throwing in visual gimmicks so absurd – and so unnecessary – they take a person right out of the movie.

Until that point, however, “Tokyo Drift” is an awfully exuberant kick in the proverbial pants. Lucas Black (“Sling Blade,” “Jarhead”) plays Sean Boswell, a California teenager with a penchant for getting into major trouble every time he steps behind the wheel. Out of options, Sean’s single mother is forced to send him to live with his father (Brian Goodman, “In Dreams”) stationed by the Navy in Tokyo. Soon the boy’s immersed into a society he hardly comprehends, the subtitles required to at least gain a wee bit of clarity nowhere near as forthcoming as the kid would like.

What Sean does comprehend are automobiles, and with the help of fellow fish-out-water Twinkie (Bow Wow, “Roll Bounce”) the American is thrust into the adrenaline-fueled world of high-octane drift racing. Soon Sean’s ego is getting in the way of his head once again. Not only does he challenge, and lose to, a charismatic racer named D.K. (Brian Tee, “We Were Soldiers”) with ties to the Japanese Yakuza, Sean also falls in love with the guy’s biracial girlfriend Neela (newcomer Nathalie Kelley). Now things are far more complicated than they’ve ever been before, trying to decide what tires to put on new friend Han’s (Sung Kang, “Better Luck Tomorrow”) car the least of his problems.

Don’t worry, it’s all just about as silly as it sounds. And that’s a good thing, because if Lin and Morgan took any of this seriously “Tokyo Drift” would be a massive waste of time. Instead, like those silly Westerns Clint Eastwood made after he got through with Sergio Leone, films like “Hang’Em High” and “Coogan’s Bluff,” this is one heck of a grandly entertaining schlocky B-movie delight. The tires screech, the engines roar, the guys hot, the girls sexy (and their outfits sexier and I’m not ashamed to admit I’m just a wee bit jealous) and the cars sizzle. The movie is everything you could hope for plus a bag of chips, the film having all the makings of becoming one of the summer’s most frivolously raucous surprises.

Then disaster strikes. The whole thing has been building towards a final race between antihero-with-heart-of-gold and villain-with-will-of-iron, doing so in such effortless abandon I could actually feel the perspiration on my palms increase the closer it came. But then the air comes right out of the movie. Not only is the race blandly unexciting, Lin can’t seem to do a darn thing to make it so. By the time things come to a head I could’ve cared less if Sean won or lost, and for a film that had shockingly won me over so completely for it to lose me just as absolutely with one misbegotten sequence was really a crying shame.

For a silly little throwaway flick like this I’m probably being a bit overly harsh. For the most part, “Tokyo Drift” is a heck of a lot of fun, and there’s a fantabulous cameo at the very end that ties all three chapters together rather brilliantly. Still, I just can’t get that climax out of my head, the bad taste left by its ineptitude almost too much for me to bear. The title may still be “The Fast and the Furious,” but the only thing speeding here is how quickly the movie falls apart.