Backmarker: Honda Flat Trackers, Part 2

If you missed last week’s Backmarker, you’ll want to read that one first to get an insider’s perspective on the development of the first Honda factory flat tracker, the NS750. It was sort of the Neanderthal to the RS750’s Cro-Magnon. Though they briefly coexisted, the NS was displaced by the RS in fairly short order. (Phew! That’s a tortured analogy; let’s get back to motorcycles.)

Jerry Griffith had conceived the first version, the NS750, right at the end of the ’70s. But after campaigning that bike a couple of seasons, it was clear—even after hiring an AMA Grand National Champion in the form of Mike Kidd—that they weren’t going to turn it into a winner.

Honda needed to take an altogether different approach. Here’s Jerry, again:

The last race we ever did was San Jose, and we finished third and fourth with it [the best finish ever for the NS at a National on a Mile track]. That was just hanging in the draft; the thing was fast—until about halfway through the race. You could see them go off the pace; it was just awful!

We could see the engine lose power as it got hot, just running on the dyno. We knew we had problems we couldn’t solve. By then, Honda was developing a big street engine, a V-twin something like the old Yamaha Virago. [The VT750C Shadow cruiser was released in 1983.] They sent us one of those motors and we tried to make a frame for it, but it was hopeless. It had a great big sump, it was wide, it dragged. It wasn’t going to cut it.

I said, “We’re better off with what they got.” Gene Romero and I flew over to Japan to talk to them. We told them we needed to start from scratch, but they wouldn’t do it. Finally, we happened to see an engine they’d built for a Paris-Dakar racer [presumably the NXR750]. It was two-valve motor, but it was perfect. I said, “We need this one here, with a full-circle crank and a four-valve head.”

They said, “It’s not possible,” but that’s how they built the first RS.

So the first RS was not copied from an XR750 at all, despite the superficial similarities. Although it’s a narrow-angle V, it’s actually 52 degrees, not 45 like the Harley, and the cranks are totally different. The Harley uses a split (“knife and fork”) connecting-rod setup on a single crankpin, and the cylinders are directly in line. The RS rods are offset, and though the cylinders are 52 degrees apart, they fired 90 degrees apart. The bikes look a lot more similar on the outside than they do on the inside.

Jerry continues:

That first year with the RS was like the first one with the NS; they’d build something and send it to us, then we’d modify it and send it back to them. The first year we ran that thing, it was so slow that we’d run it in practice and then use the NS in the final, and maybe have one RS in the race.

We experimented with all kinds of cranks. The NS [and the first RS] had lots of power, but it spun the tire. We finally got some cranks that shook bad but really hooked up. We had one RS motor that we chopped and changed all kinds of stuff on, and Hank Scott won Du Quoin with that. We sent that back to Japan, and they copied that and sent a bunch of those back to us. They were fire-breathing sumbitches! Once we’d worked the bugs out of it, the RS annihilated the Harleys.

Honda said, “Now what do we need to do to win [the Grand National Championship]?”

I said, “Here’s the deal; there’s three guys we can’t beat—Scotty Parker, Ricky Graham, and Bubba Shobert. If we get one of those guys, we can win.” We couldn’t get Scotty, but we got Ricky and Bubba. I’ll never forget the day we went to the Sacramento Mile, and Ricky and Bubba, down the back straight, they were gone. I thought, The fans aren’t going to like this.

By that point, I’d built a lot of motors that I thought would be good, and they weren’t. It was a long old deal, but it was rewarding when we finally started to win. [The AMA] let us win a couple of years and then restricted us. [At Harley-Davidson’s insistence, the AMA passed the restrictor-plate rules that were still used through last season. The four-valve heads in the RS flowed with a lot more velocity than that two-valve heads in the XR750, and the restrictor plates hurt the Honda’s performance more than the Harley’s.]

When they restricted us, it pissed Honda off. They had big ideas for racing [in the States], and when Harley was in trouble [around 1980], Honda was going to build engines for them and all kinds of stuff. But when they restricted us, and that was the end of it.

Ricky Graham won the GNC on an RS in 1984, and Bubba Shobert took over and won in ’85, ’86, and ’87 before making the transition to fulltime road racing. My little reference library’s in post-move trauma, and I don’t know off the top of my head when exactly the AMA instituted the restrictor-plate rule. I want to say for the ’86 season. Maybe someone can write in to clarify that point.

Although Honda felt unfairly penalized by the restrictor plates, anger at the rules committee was only part of the reason they disbanded their factory flat track team. The mid-’80s were not a great time for the Japanese manufacturers. The “new” Harley Davidson company was clawing back a lot of the traditionalist/cruiser market share it lost over the 1970s. The response to the Honda Shadow was lukewarm, and it was presumably the bike Honda hoped to promote by racing flat track. Also, Honda was beginning to really focus its superbike effort.

Despite being hamstrung by the restrictor plates, the RS750 remained popular with privateers, so Honda maintained a presence on the flat tracks. Privateers liked them because RS750 motors were delivered fully assembled and ready to bolt into a frame, whereas the XRs arrived as a collection of disassembled and barely finished parts. And the Hondas had much longer service intervals; many privateers only rebuilt them once a season, whereas the Harleys needed almost weekly attention.

For a while, the playing field was about flat (er, make that “level”) until Mert Lawwill realized the significance of the RS750’s Nikasil cylinder coating. That allowed the Hondas to run much tighter piston clearances with better heat transfer (among other benefits). Once Mert started plating his XR750 barrels, the Harleys again eked out an advantage. Still, Ricky Graham won the championship on a privateer RS again in ’93.

So…

My conversation with Jerry Griffith may go a little ways toward disabusing motorcycle historians of two prevailing myths.

The first is that the NS750 was a bad motorcycle. It wasn’t. Or at least, it certainly wasn’t all bad. If Grand National races would’ve been shorter—admittedly, they’d have to have been a lot shorter, like five laps total—it would have been a winning bike. It had one flaw—that overheating problem—which couldn’t be tuned out of it. Fixing that would’ve taken new castings, an expense that simply didn’t make sense.

The second is that the RS750 was a copy of the XR750. I wonder how that got started? Sure, the two motors look superficially similar; at a glance, the RS’s 52-degree V-angle is hard to tell from the XR’s 45-degrees. But unzipped, they’re totally different.

I imagine Harley-Davidson saw it as plagiarism. And I’m sure Allan Girdler’s account about Honda taking an XR750 motor back to Japan is accurate. But all the OEMs have competitive fleets, and studying rivals’ products isn’t necessarily plagiarism. It’s often just due diligence.

Speaking of diligence, there’s some thing else you should due. Check in with www.roadracerx.com tomorrow for Chris’ week-in-review. You’ll find me back here next Thursday.