As a teenager growing up in El Paso, Dave Hennessy loved tooling around on his dirt bike, with that love for the ride taking him to plenty of competitive motocross races.

Almost four decades later, Hennessy is still astride the saddle, this time a contender for a national championship.

But Hennessy is only as good as his partner, Jim Vietti. Vietti, who lives in Taylor Ranch, is with Hennessy every time he races - he's in the sidecar attached to Hennessy's 500-pound bike.

"It's a VMC with a Zalbo engine, a 700-cc, two-stroke, with 83 horsepower," Hennessy said. "The top speed? The vehicle can do 75; on a small track, maybe 60."

Hennessy, a longtime resident of Rio Rancho, will be at the handlebars Saturday, joined of course by Vietti, racing at Sandia Motorsports Park in west Albuquerque.

The longtime friends are conjoined in this sport by the sidecar, in which Vietti will be diving from left to right, counteracting Hennessy's turns, and trying to remain within the sidecar on the various jumps of the twisting motocross course.

The duo is second in the points standings for the championship class of the American Motorcyclist Association. This weekend's event is the fourth of five in the National Sidecar Motocross championship series, with Hennessy-Vietti 12 points out of first place.

The fifth race in the series is in Tulare, Calif., on Oct. 22. Teams count their top four finishes, discarding one event.

Hennessy's brother Stephen and his partner (Brian Kohl) have raced in the heavyweight class, which they lead a small field, and are sixth in the championship series.

Hennessy compares his team to that of a married couple; sure, there a few disagreements, but to be successful, it's a team effort.

And Vietti's half of the effort is much tougher, he admitted.

The two work out regularly at Defined Fitness, Hennessy said. "Racing motocross just beats the hell out of us."

It's not easy staying mentally tough and physically strong when the dips and turns on the course are so demanding on one's body - especially one that turned 52 years of age on Wednesday.

He didn't plan to do anything special in light of his birthday, saying, "I'll try to keep it calm so I'm 100 percent on race day."

Al Wenzel, a coordinator for the National Sidecar Series, said sidecar racing has hit the skids in recent years.

"It was a much bigger deal in the '70s," Hennessy pointed out, and Wenzel said there was a time when it was big in the Midwest, Pacific Northwest and Southern California, where it still remains a popular sport.

Wenzel had a few reasons for the demise: New motorcycle race tracks have strayed from the type of course conducive to sidecar racing, many of the oldtimers no longer race, and all the equipment is built in Europe. Wenzel noted that the recent surge in gas prices has curtailed some of his team's racing trips in his RV.

"Sidecar racing is very different from standard motocross," Wenzel explained. "It's two people on one machine and they have to work together as a team to get around the race course.

"You have to see it to really understand. If those two guys (there is one female passenger in the series; she's on the point-leading tandem) are not in synch and doing their own specific job at the same time, they can tip over," Wenzel said. "It's a unique melding of two totally different jobs on one machine."

Basically, Wenzel added, "The driver sets the tempo of how fast the machine going to go and the passenger dictates how much of that tempo he can achieve.

Needless to say, teammates must be on the proverbial same page, or not finish first or, worse, crash.

Although Wenzel said he expected only five or six sidecars racing Saturday, with practice laps at 9 a.m. and the first race at 10, he said the event will be fun for spectators to watch.

The contestants will have two races, and then combine their finishes to see who is first, second, third, etc., overall. In the event of a tie, Wenzel said, the second-race finish is the tie-breaker. For example, a first- and a third-place finish, respectively, would finish lower than a third- and first-place finish.

"Those guys are in a point battle," Wenzel said.

Hennessy certainly isn't in this sport for the money. The most the two have won is the $900 they had to divvy up at Pikes Peak, although he said they also picked up two sponsors to help defray some of their expenses.

Hennessy said he plans to continue racing for a long time.

"Age-wise, I'm sure we all get slower, but there is a driver that's about 60, and a passenger almost 60 that does it," Hennessy said. "I've raced pretty raced pretty much all my life."

In addition to being the driver, Hennessy, who worked as a teen at a Honda shop in El Paso, is the team's mechanic.

"I pretty much do all the work, which is how I like to have it," he said. "West Honda (in Rio Rancho) helps me with some stuff, as far as parts."

Hennessy knows both roles: "I spent 18 years in the sidecar; I'm the driver now," he said. "I get scared more than my passenger."

Hennessy was in the Air Force, then worked for Texas Instruments before moving to Rio Rancho to work at Intel. He recently left that job and has a new position as an electronic technician at Advent Solar.

"It'll be a pretty spectacular thing," Hennessy said, looking forward to the races. "If we do good this weekend and mathematically we can still win it, we'll go to (Tulare)."

For more information on the weekend's activities, see www.sandiaclassic.net.

To learn more about sidecar racing, visit www.sidecarcross.com.