After breaking up 20 years ago, a reunited Grand Funk Railroad plays a sold-out show at New York's Beacon Theatre tonight and at Los Angeles' Greek Theatre May 2. Together \again, vocalist and guitarist Mark Farner, bassist Mel Schacher and drummer Don Brewer will perform as the power trio they once were, and as a power trio plus 40-piece \orchestra for new arrangements of hits like "Mean Mistreater," "Bad Time," "Loneliness" and "I'm Your Captain."

\\Formed under the influence of Jimi Hendrix, Cream and the Vanilla Fudge, Grand Funk in their day had eight Top 40 hits, two million-selling singles -- "Locomotion" and "We're \An American Band" -- and, in 1971, sold out New York's Shea Stadium faster than the Beatles had a few years prior. But as loved as they were by legions of fans, Grand Funk was the band the critics loved to hate. Ten platinum and 12 gold records later, and with 14 million records sold worldwide, does it still hurt?

\\"Well, the critics in New York and Los Angeles panned us, but not in the rest of the country," Brewer said during an interview in New York earlier this month. "And, yes, I thought it was very unfair."

\\"We'd see the reaction, with the crowd going nuts, people swinging from the rafters -- just an incredible energy level," added Farner. "And then we'd get slammed, and we'd\think, What show was this guy at?"

\\Certainly, Grand Funk was a rock & roll band to its core -- sweaty, hard-driving, direct and elemental. But this is also a band that produced two Top 10 hits with "We're An\American Band" and "Locomotion," songs that benefited from the band's strong groove and the production of Todd Rundgren, who worked with the band for two albums,\starting in 1973.

\\"The idea for 'American Band' came from our manager at that time," said Brewer, who wrote the song. "We had just gone through a lawsuit with our previous manager and producer, Terry Knight, and we ended up without a pot to piss in after having six gold albums and traveling around the world. So we were in a depression, but still had to come up with another album for Capitol. Our manager said to us, 'Just write songs about what you do. You're an American band, just write about that.' So that was my inspiration for that song."

\\For those unfamiliar, or who don't recall, "American Band" is a classic first-person tale of sex, drugs and rock & roll. Not that the guys remember it that way....

\\"The stories?" Don asked, feigning confusion. "You mean, did we ever trash a hotel room? Okay, yes."

\\"No, not really," counters Mel. "But we did trash a ballroom at the Beverly Hills Hotel during an awards presentation attended by all of the media on the West Coast."

\\"See, they wheeled in this huge cake, like a multi-tiered wedding cake with Uncle Sam on top, for 'We're An American Band,'" Farner said. "And just as we were cutting it with\this massive knife, somebody yelled 'Food fight!,' and we dove into that cake and started slinging it. And the press came up, and they were grabbing cake and throwing it, and we\had frosting on the chandeliers, on the ceiling. The velvet curtains were just frosted. It cost $14,000 worth of damage, and they banned us from ever coming back."

\\"We got paranoid the next morning, thinking Capitol was going to fire us or that we were going to get in a lot of trouble," Schacher added. "So we called them up, and they loved it. We couldn't afford to buy that kind of publicity. They had to pay for the damage, and they still thought it was great."

\\"And that's the only thing we ever did," Don said, to laughs all around.

\\With their reunion, the band is playing three concerts to benefit the Bosnian Relief Fund, a charitable organization that provides food and supplies to victims of the war in Bosnia-Herzegovina. Tonight's New York concert is to include special guests Peter Frampton and Leslie West. All three shows, including the kick-off performance that took place in their hometown of Detroit on April 20, feature appearances by a 40-piece orchestra that includes members of the Sarajevo Symphony.

\\The band also plans to tour Europe and Japan in June and July, the United States in August and September, play a benefit performance in Sarajevo in September and record\new songs with producer Ron Nevison.

\\"We started talking seriously about this tour in 1994," Brewer said. "We had lots of different offers, but if we were going to do a reunion, we wanted to be true to our fans, to what their memories of the band are."

\\"So many bands have come back and maybe they've got the brother of an original band member, certainly not all the original members, and they team up with other groups. They\call them 'heritage acts.' But we didn't want to do that. This is the three real guys. And we felt like this organization, which benefits Bosnian children and other victims of the war, was something we wanted to be associated with."

\\And so, two decades after they rocked teens across the country -- and fluttered the hearts of so many female fans -- Grand Funk is back on the road, same as it ever was. Well, sort of.

\\"It's easier now because of our experience," Farner said. "And we all agreed that if we couldn't have fun, we wouldn't do it."

\\"What's harder for me is that we all have other things going on in our lives," Brewer said. "When we