Many Americans assume that the black communities in Kingston, Jamaica, and London contain reggae fans exclusively. In fact, mainstream American soul is just as popular in those communities, and in recent years the cities have produced soul records that rank with the best in the States.

London, in particular, has been the source of a "Britfunk" movement that has produced fine bands like Heatwave, Lynx, Central Line and Imagination. The best of the soul imports, though, are two Juniors: London's Junior Giscombe--who sounds uncannily like Stevie Wonder--and Kingston's Junior Tucker --who sounds like Michael Jackson.

Norman Giscombe Jr. goes by the stage name of Junior. His debut album last year, "Ji," resembled a young Stevie Wonder with its straightforward but irresistible dance hits: "Mama Used to Say" and "Too Late." Junior's follow-up album, "Inside Lookin' Out" (Mercury 812 325-1 M-1), doesn't sound like Wonder quite as much, but certainly shares the musical and lyrical ambitions of Wonder's later career.

This time out, Junior expands his always attractive melodies with fuller arrangements. His agile high tenor skips in and out of the melody and a backing choir chants the chorus.

Bob Carter's synthesizers highlight certain melodic figures against the steady backbeat, and Carter's piano explores the restless chord progression as the horns punch out counterpoints. The stops and shifts keep the songs from growing stale.

Carter, who plays all the keyboards, co-composed the music and produced the record. Like Wonder, Marvin Gaye, Luther Vandross, August Darnell and Earth, Wind & Fire, Junior and Carter are trying to reconcile rich melodic arrangements with the modern, techno-funk dance beat. These are artists who hold out the promise that the romance of a heartbreaking tune, the intelligence of a mind-teasing arrangement, and the sensualities of a hip-swiveling beat can all coexist. The listener doesn't have to give up one to get the other.

Junior's lyrics reflect this ambition with tales of missed connections and the struggle to set things right. "Communication Breakdown" describes misunderstandings on social and personal levels; and the industrial sound effects and bass-heavy funk suggest technological alienation as one cause. "Women Say It" acknowledges that men just don't understand the special trials of motherhood over a catchy, childlike call-and-response tune. "F.B. Eye" is a nightmare narrative, complete with ominous music, about a hard-working father being falsely accused in a police lineup. More upbeat is "You're the One," in which Junior's exultant cries of love are backed by Carter's bubbling stew of unusual synthesizer sounds.

Although only 16, Junior Tucker has been a star in Jamaica for 11 years, with a long string of Top 10 hits there. His first American release, "Jr. Tucker" (Geffen GHS 4009), teams the young Jamaican singer with U.S. star Ray Parker Jr., who produced the album, wrote three songs and played guitar, bass, drums and keyboards. The Tucker-Parker team produces a frothy mix of giddying lead vocals, breathy harmonies, a spare but firm dance beat and instantly hummable melodies.

The arrangements are stripped clean of any excess; the buoyant teen-age optimism of Tucker's voice bounces along unencumbered by instrumental counterpoint or weighty lyrics. Like Michael Jackson, a fellow soul prodigy, Tucker practices the new international pop--light and breezy. The combination of sweet, seductive melodies sliding right across the top of a brisk, regular dance beat has been applied by many of the biggest international stars--the Jacksons, Abba, the BeeGees, the Police and Men at Work.

All eight tracks on "Jr. Tucker" are potential singles. The first single, Parker's "Bad Girls," is more bottom-heavy than the rest, with Tucker sharply snapping off phrases as he talks about having fun with promiscuous girls. Charlie Roberts' "Take a Message (From My Body)," a big hit in Jamaica, has been redone by Parker with horn and backing voices that help along the soothing romance.

Parker's ballads "Mr. Telephone Man" and "Going Through School and Love" capture the timeless innocence of teen-age heartbreak. Tucker's similarity to Michael Jackson is unmistakable on Ish Angel's "I Was Made for Dancing," where he uses the same breathless tenor, the same clipped phrasing and the same scat cries that give both singers their impatient urgency.