Backmarker: Honda NS750 Flat Tracker

January 22, 2015
Mark Gardiner
Mark Gardiner
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In 2001, Mark Gardiner gave up his career in advertising, and moved to the Isle of Man to live out his childhood dream of racing in the TT. After returning to the U.S., he wrote a memoir of that experience, Riding Man, which is now in development as a feature film. His column, Backmarker, looks at everything from the motorcycle industry as a whole to intensely personal 'inside stories.'

A Rare Honda Stumble: The NS750 Flat Tracker

A few years ago, I tracked Jerry Griffith to his ranch in Northern
California. Thirty years earlier, he’d spearheaded Honda’s official
effort to build a competitive flat track Twin.

The first race of the 2015 Grand National Championship is less than two months away. Flat track fans wonder, how long will it be before a non-Harley rider wins the championship (again)? Last season, Bryan Smith and his Kawasaki were in the running until the last flag fell, but over the course of the season Jared Mees and his Harley-Davidson were a little bit better.

Kawasaki and Ducati – and to a lesser extent Suzuki, KTM, and Triumph – are coming on strong. I’ve got high hopes for the new Yamaha MT Twin, too. But, 2015 will be the 21st consecutive year in which the number one plate’s been affixed to an XR750. Moral: It ain’t easy to displace the venerable XR750, especially if you’re starting with a street bike motor. Back in the ‘80s, even mighty Honda tried and failed.

As Tolstoy said, “All happy families are the same, but every unhappy family is unhappy in its own way.” With that in mind, stories of failure can be more interesting than stories of success.

Herewith, the tale of the Honda NS750 flat tracker…

Most of Honda’s explosive sales growth in the U.S. market, through the ’60s and ’70s, was accomplished without a concerted or comprehensive AMA racing program. There were brief periods of official interest, but somehow American Honda seemed immune to the racing bug, at least by comparison to the U.K. and European subsidiaries, and RSC (Racing Services Corporation, the predecessor to today’s HRC) back in Japan.

But by the late ‘70s, American Honda had to admit that a Grand National Championship would be a marketing boon. That meant building a competitive flat tracker. Harley-Davidson had worked the bugs out of the XR750 over the previous decade, and shown that V-Twin power was the way to go.

It was easy to source a proven frame from one of the indie frame shops, like C&J. That all made sense. What didn’t make any sense at all was anyone at Honda looking at their CX500 and saying, “We’ve already got a V-Twin, let’s race it.”

Yes, they actually decided to race an underpowered, shaft-drive, transverse-V commuter bike – a model London motorcycle couriers called ‘the Plastic Maggot’ – in AMA Grand Nationals.

It was a bit like Motorcycle USA signing me up to fight in the UFC. Of course to have any chance of being competitive, they had to punch it out to the 750cc displacement limit. That was a bit like putting me on a heavy dose of steroids; it sounds kinda’ fun but there were bound be complications.

According to AMA homologation rules, Honda had to build parts for 25 motors, but only five or six Honda NS750s were ever assembled. Privateers hardly clamored for them, since it wasn’t a winning bike.

The accepted wisdom has long been that the NS was a flop, and that Honda’s riders had their asses handed to them by guys on Harley-Davidson’s XR750; the one exception was Scott Pearson’s win on the Louisville half-mile.

A few years ago, I sought out Jerry Griffith, who chopped and turned that CX500 motor to create the very first NS750 prototype. Jerry was the hub of all of Honda’s factory efforts in Grand National flat track. He did everything from building motors to managing teams. He conceived the NS, and then convinced Honda to build the RS – which was a winner. After talking to him, I realized that the NS’ reputation as a loser was an oversimplification…

Griffith was a sucker for punishment when he accepted the assignment of turning the plebian CX500 commuter (above) into the star-crossed NS750 racer.

Once again, a classic American racing story goes back to Kenny Roberts. The King and Jerry were partners in a motorcycle frame business. Just before Kenny went to Europe, they built a little TZ250 flat tracker for Kenny to ride in Houston. After Kenny left, Jerry let Jeff Haney ride it at Ascot, and he started winning on it and just kept winning. He won every race that year.

Despite Haney’s impressive season, Yamaha didn’t want anything to do with them the next year, so they got an XR500 Honda dirt bike motor through Dave Bird – he was a dealer and active in flat track, building and selling parts like exhausts.

Well, why don’t I just let Jerry pick up the story from there…

“The frame was just a one-off frame I built for Jeff, with that 500 Single motor. Jeff raced that in the Junior class at Ascot, against Harleys and everything. And he won every race he entered. So Honda started helping us. It was between us or Mickey Fay. He’d won Houston on a Honda, but we got lucky and they picked us. Honda also sponsored a special race for Singles, and either Jeff or Mickey won every one of those. I’m going to say that was ’78 or ’79.

“Dennis McKay, Honda’s race boss at the time, was really a dirt track fan, and he was wanting to get Honda into dirt track. We knew we couldn’t compete with the Harleys if we only had that Single, but Honda didn’t have a 750 Twin; they only had Fours. So that [the CX500] was all we had to work with, it was a sorry deal. He gave me a CX500 motor. We turned it around sideways and grafted a sprocket on it.

“We couldn’t turn the heads, so the guy’s leg had to go between the carburetors. It wasn’t real comfortable. Initially we didn’t change the displacement. Honda was already making a turbocharged 600cc version, but they didn’t have one of those to give us. We thought that if we could at least get the 600, we’d get a little closer. The 500 had no power, it was at least 10 mph down on top speed; it really wasn’t competitive at all.

Here’s an early prototype, with the Transverse-Twin turned 90 degrees and converted from shaft to chain drive.

“Mr. Irimajiri [the legendary HRC engineer who created the oval-piston NR500–MG] came to the San Jose Mile, in ’79 or ’80, and watched it run; he really liked it and got his picture taken sitting on it. The first thing you know he built – well, we got hired by them—and he built five or ten of those engines. [By ‘those engines’, he means a bored and stroked CX500 engine displacing 750cc, converted from shaft to chain drive–MG].

“We built the frames for them. We tried quite a few frames, the first ones had twin shocks then we tried a monoshock. Once we got the chassis working, we sent it to C&J and they made, like, five of them.

Jerry in about 1981  with an NS750 prepared for Freddie Spencer.
Jerry in about 1981, with an NS750 prepared for Freddie Spencer.

“It was a long-term deal trying to win with that thing. The two guys that helped the most to develop it were Ted Boody and Hank Scott. We’d go back east and run all those non-National miles from Kansas to Ohio.

“At first, I was the mechanic, the pit boss, truck driver… as it got bigger, I couldn’t handle all that stuff. They wanted me to be the crew chief, but then they wouldn’t have let me work on the bikes, so I talked them into hiring Gene Romero to be our crew chief.

“The mechanics that worked on the bikes with me were Dan Murrell, Dennis Jones, Dave Bird.

“We started from scratch. When I raced, bikes didn’t even have shocks, so I learned from Kenny. I didn’t know nothin’, but I knew enough to keep Jeff happy. I learned a lot from Hank and Ted Booty, they helped me a lot. Mike Kidd had a lot of input, so did Terry Poovey and Mike Pearson. Most of them didn’t like it!

“The problem wasn’t a lack of power. In the end, we got 90-92 horsepower out of it. We were spending money trying to win. I did a lot of dyno work with it myself, but lots of other people helped too; I had Jimmy Dour at Megacycle, Jerry Branch built heads, Kenny Augustine… But its biggest problem was that they’d bored it out so big, it didn’t have enough room [in the water jacket] around the sleeves. It would get steam pockets in it, and overheat and slow down. We couldn’t run anti-freeze; if we could’a run anti-freeze it wouldn’t have boiled it out. But it was a rocket for four or five laps.

The same bike a few months later. I guess Freddie thought Jerry had too much time on his hands, and needed something to work on.

“I mean, Hank once told me it was the best handling bike he’d ever ridden, but… I think it ruined Jeff Haney’s career. He had tons of talent, but he got to the point where he had no confidence in it. I kept telling Jeff, ‘have patience,’ but he was just a young kid.

“Mike Kidd took more of a professional approach. He had won the number one plate on a Harley the year before, and he approached it like a job. Mikey was at the end of his career, and he’d already been there and done it all. But he got a lot done; we made a lot of finals. Everyone who was involved wanted to win, but to start out and beat them Harleys was not easy. They’d been winning forever.

“The one time we won [a National, at the Louisville half-mile] it just fell into our hands. Scott Pearson won the last chance qualifier, and they lined everyone up on the front row. Everyone got to pick before Scott, but there was a little hole right on the inside, on the pole, and Scott lined up there.

“The groove at Louisville was only about three feet wide. If you tried to pass on the outside, you lost about five spots. Scott was such a holeshot guy that I said, ‘If you can get to the front, there’s no way they can pass you.’ He just had that thing sideways for about 25 laps, and every time someone tried to pass him, they’d pull out and just go backwards. It was Scott Pearson that won the race, not the motorcycle.”

So, I stand corrected. The NS750 wasn’t an abject loser. It handled well and was fast, just not fast enough for long enough. To make competitive power, Irimajiri had to bore the cylinders clean out of it and fit much larger sleeves. There were narrow spots where the sleeve constricted the flow of water in the water jacket, and steam formed there. As the temperature went up during the races, the bike went slower and slower.

Honda bought the #1 plate in the 1982 season, when it hired GNC Champion Mike Kidd to continue development of the NS750. Here he is at the legendary Ascot half-mile track in Gardena.

“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–MG.] That was just hanging in the draft; the thing was fast – until about half-way 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–MG] 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–MG]. 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.”

The Honda RS750 was a purpose-built production racer, designed with one thing in mind: shoving the Harley-Davidson XR750 aside on American dirt tracks. It worked, but that’s another story.