Backmarker: Tying up NS/RS750 Loose Ends

Last week, I asked Backmarker readers to help me remember when the AMA introduced restrictor plate rules in flat track. I was gratified when no less an expert than Chris Carr emailed me to say that the rules came in for the 1987 season. “Bubba Shobert, as you mentioned, went on to win the Championship despite all of the grumblings about restrictors hurting the Honda more than the Harley,” Carr wrote. “I guess in retrospect that Bubba’s third title was probably his most impressive.”

Another reader, Mike Durkin, disputed my suggestion that the RS was based on a prototype Paris-Dakar racer. “ The RS750,” he wrote, “was made from the shaft drive XLV750R.”

That seemed plausible to me. Last week, I was only speculating that the bike Jerry Griffith and Burrito had seen in Japan was the NXR750V. Jerry didn’t remember what that bike had been (and may well have never known its exact designation). I settled on the NXR750V because it was a Dakar Rally racer from the right period, it was an air-cooled 750, and because Jerry told me it was a narrow-angle V, but not a true 45 degrees. The NXR was, I thought, 52 degrees—though when I tried to go back and confirm that, I couldn’t find my original source for the figure.

So when reader Durkin brought the XLV750R to my attention, I looked at that bike as a possible source of the RS750’s basic architecture. It was never sold in the U.S., but was sold in Europe in the mid-’80s. I don’t think it was ever raced in the Dakar Rally (at least not in its shaftie guise), but it was styled as an early adventure bike and has the required 750cc air-cooled motor. It’s listed in a couple of sources as having a 45-degree V-angle, and in side-on photos the castings bear a strong similarity to an RS750. (Incidentally, it went on to spawn the still-cult-fave Honda Africa Twin.)

So I called Jerry back and asked him if he thought that the XLV750R might have been the bike he saw at Honda. He was emphatic that the V-angle was not 45 degrees. “The Harley was a true 45 degree motor,” he told me, over the sound of an air compressor running in his shop. “I’d have to go check my notes to remember what the RS angle was, but I know for sure it was not exactly 45 degrees.” He was also positive the bike he saw wasn’t a shaft drive, and that the bike he saw had two-valve heads (the XLV had three-valve heads).

In frustration, I called my friend Chris the V and asked him to walk down the hall from his office and measure the V-angle of an RS that’s parked at Motion Pro. He sent me a photo that makes it seem as though the included angle is slightly less than 45 degrees. It’s definitely not 52 degrees, so I was mistaken somewhere along the line.

Why is it that the more I learn, the less I seem to know? I hate it when that happens. I suppose that eventually, I may determine what bike Jerry saw on that fateful day in Japan. Not that it was necessarily either the NXR750V or the XLV750R. Those two probably have a lot of shared DNA, so it could have been a common antecedent or some hybrid. Maybe I’ll lean on my friend Brian O’Shea, who has friends at the Honda Collection Hall, and see if anyone there happens to know.

It’s all a bit moot anyway, since we’d only be talking about engine castings. Once the first RS motors came over, Jerry began a long process of experimentation in order to find something that would make the bikes hook up.

“When we first got it,” he told me, “we took it to Ascot and it was fast right out of the box.” The problem was, it was only fast on Ascot’s crazy dirt. Anywhere else, it just spun while the Harleys hooked up. Over the course of many races, Jerry changed crank timing and flywheel weight to find a setup that worked on dirt from our own planet.

It was interesting talking to him about it, because that challenge was more complicated than just making the bike fast. “The rider’s the king,” he said. “If he’s not comfortable, it doesn’t matter how fast it is.” He built bikes that hooked up but shook too much for the riders to feel they were under control, and he built bikes that hooked up and were fast but which the riders didn’t like because they felt slow. (Personally, I love bikes that are fast but feel slow! I guess that makes me a chicken, and explains why I never bothered trying my hand at Grand National racing.)

Finally, after one of those extensively tweaked RSs scored its maiden win at Du Quoin, Jerry sent that version of the motor back to Japan, and it became the standard for all subsequent race motors. It really doesn’t matter what motor provided the basic castings and architecture for the RS750; it was for all intents and purposes a made-in-America solution for a uniquely American style of racing.

In his email to me, Chris Carr added, “Your articles have reminded me that [the brief flourishing of the RS750] was the end of an era [when more than one brand was really competitive in Grand National racing], and those days will be missed. As my career winds down, I hope that the new AMA Pro Racing can somehow restore what has been missing since then. In my humble opinion, the days of us—American brands—versus them—other brands—are over.”

In a subsequent phone call, Chris told me, “Back when Ricky and Bubba were winning on the RS750, the crowd booed them because they weren’t on Harleys. But now, when an Aprilia or a Suzuki gets on the box, no one’s booing.”

Chris has long been a Harley-Davidson rider. (He earned a salary from the factory for flat track and, for a while, as a road racer with the ill-fated VR1000 superbike.) He’s hugely appreciative of the support he’s received; he respects Harley’s ongoing investment in the sport. Still, I get the impression that he’d like to see a somewhat more level playing field for rival brands. Although Suzuki, Aprilia, and the like are allowed a larger displacement than the venerable XR750 Harley-Davidsons, the extra 250cc are no advantage, because in flat track, it’s all about traction.

Years ago when the Supertrackers first made their appearance at Grand Nationals, Chris told me, “If we ever figure out a way to make these things hook up, we won’t have a single track that’s safe enough to ride them on.” He expanded on that thought with me last week, saying, “We have some Airfence now—not enough of it, but at least it’s in the main impact zones, and we appreciate that. But no one’s pushing back the fences or putting in gravel traps.”

I got the impression that Chris feels that at the moment, power, tires, chassis technology, and tracks are all in a precarious balance. With grip, more power would throw them dangerously out of whack. I think he’d welcome horsepower limits at Grand Nationals, set at a level (somewhere in the 85 horsepower range) that would allow other manufacturers to play a more competitive role. “When has making the bikes faster actually improved the racing?” he asked, rhetorically. “It didn’t in MotoGP!”

“I think,” he told me, “that a lot of the changes DMG are making to the road racing series would work better, and be more welcome, in flat track.” He feels (and I agree with him) that it wasn’t the handful of riders making a million-plus who defined the health of the road racing series. No flat tracker made anywhere near that much, but that’s beside the point; the health of either pro discipline depends on the top twenty or more riders all earning a decent living.

“The biggest problem with DMG’s takeover of flat track is this economy we’re in,” he said. But he’s confident that the sport will prevail. “In 1985, when I came into flat track, people told me, ‘You don’t want to get into flat track; in five years, it won’t even exist.’ Well, twenty-five years later, I’m still here, and flat track’s given me everything I have.

“I’m cautiously optimistic about our future under DMG,” he concluded. “The Indy Mile on the MotoGP weekend was a great event, with our most diverse crowd ever.” He spoke of a spec fuel possibly helping the cause of privateers (basically everyone, in flat track) and of the possibility of a return of Grand Nationals to the West Coast (although he cautioned that travel expenses would have to be amortized over more than one race).

I’m hoping to get a little phone time with Mike Kidd and Roy Janson, who are managing flat track for DMG. I’m interested in their vision for the future of this most American form of motorcycle racing. I agree with Chris that flat track is less of a political minefield than the AMA Pro Road Race series has proven to be, and more open to changes. If I hook up with them, then you, Backmarker readers, will be the first to know what they had to say.