Noguchi’s unicorn racers of the 1970s

Noguchi’s unicorn racers of the 1970s were hopped-up Yamaha dirt bikes with a twist.

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by John L. Stein

Some of the greatest motorcycle companies started with a simple dream.

Soichiro Honda began making piston rings after World War II. The Ducati brothers offered an auxiliary engine, the Cucciolo, to power bicycles. And William Harley and the Davidson brothers developed a single-cylinder motorbike in a wooden shed. While these companies flourished to become global leaders, far more made a similar start, found a toehold for a while, and then misstepped, ran short of ideas, capital or leverage, and faded away. This latter scenario describes Noguchi, a Japanese company that made racing parts for various Yamahas during the 1970s.

Credit company founder Taneharu Noguchi, Yamaha’s first factory rider and later team manager, with great timing in building go-fast parts for the company’s growing lineup of dirt bikes. Using chrome-plated aluminum cylinders — together with revised port shapes, oversize reed valves and carburetors, and bespoke racing expansion chambers — Noguchi turned production bikes into raging racers. Models ranged from 80cc and 90cc tiddlers through 100cc, 125cc, 175cc and eventually 250cc machines. Later on, Noguchi even produced a liquid-cooled cylinder head kit that further evolved production bikes into works-type replicas.

Not exactly “factory”

The term “replica” should be emphasized here, as Noguchi was neither Yamaha’s racing department nor Yamaha’s own Genuine Yamaha Technology (GYT) division. It was a standalone company that developed, produced and distributed unique parts dedicated to the Tuning Fork bikes. Along the way, confident advertising from its U.S. sales agent, an Atlanta company called Dirty Distributing, arguably blurred the lines between Noguchi parts and prototype race-shop parts. This was largely done through using the term “factory works” in its literature. As any aware racer knows, “factory” and “works” specifically means the race department of a motorcycle manufacturer, not an aftermarket company.

Nonetheless, the selling proposition for Noguchi was solid. During an incredible decade of performance advances for dirt bikes, the company offered a good range of items necessary to turn up the wick on commonly available Yamahas, including the GT80, MX100, MX125, YZ125, MX175 and similar. Its advertising was emphatic about what customers would get. “Go all the way,” the literature read. Touting power gains was key, for instance that a kit for a MX125 would increase horsepower from 22 to 30 — a 36-percent gain. Similarly, the boost for a kitted MX175 was from 24 to 33 horsepower — a 38-percent boost. You get the idea. Kits cost from $97 to $300, based on period documents.

Speed costs money

Logically, even in the early 1970s, performance cost money. Yamahas were good enough bikes, but they weren’t expensive “exotics” like Maico, Husqvarna or CZ. And so, the people who bought them were likely drawn to the “bang for the buck” that bolt-on Noguchi kits promised.

Stage I parts typically included a cylinder (and sometimes cylinder head), piston and ring, up- or down-pipe, and other bits to make converting from “stock” to “factory works” simple. Along with instructions, kits even included a can of Blendzall racing castor — perfectly reinforcing the buyers’ racing pretensions. A Stage II kit included a larger reed-valve housing and reed-valve assembly, upsized carburetor, and sometimes an uprated connecting rod. This latter inclusion, though, took the Stage II kit past being a Saturday-morning bolt-on affair into the territory of an entire engine disassembly, and requiring a shop with a press and crankshaft alignment jig to install the rod.

A personal quest

The reason for this article is a bit personal, as I’d heard about Noguchi for years but didn’t know much except the company made trick chrome-bore cylinders and heads. And also, I acquired the bike shown here through a random gas-station encounter with a fellow vintage racer while returning from an AHRMA national. Riding the bike and studying its componentry made me hungry to know more about this mysterious long-ago brand. It seemed like the shy unicorn in the woods of a Harry Potter movie: Noguchi parts — storied but rarely seen. And the plum atop this knowledge search was an excuse to call longtime racing acquaintances to ask about Noguchi. Here are their comments.

Scott Clough

Veteran 2-stroke race engine builder Scott Clough, proprietor of Scott Clough Racing in Yucca Valley, California, stands behind the Noguchi’s principal of a chrome-plated barrel. “One of the fundamental improvements a race-engine tuner must make is to manage heat,” he begins. “Higher horsepower means more heat, and more heat requires more heat dissipation. An iron cylinder liner does not transfer heat very well, and this is where the chrome cylinders like Noguchi used were desirable. They allowed the parts to live happier together for a longer time under the loads of racing.

“With an iron liner a lot of wear occurs around the intake port, but a chrome-plated cylinder should stand up much better. And the better the plated cylinder holds up with use, the better it will allow you to run multiple pistons before replacing or re-plating. Iron liners are commonly re-bored for oversize pistons, but when a chrome cylinder wears out, instead of boring it, you can plate it back to the size it was.”

Clough adds some technical insight that weekend mechanics might never learn. “The chrome plating on Noguchi or Yamaha YZ cylinders is not compatible with chrome rings,” he notes. “Chrome bores need iron rings. Also, chrome bores are not the same as Nikasil bores, which are a nickel-silicon-carbide matrix, a different plating material. Actually, Nikasil liners are even more durable, transferring heat and retaining oil very well. That was an improvement beyond chrome bores that allowed even more horsepower to be made more reliably.”

Dave Rymal

“Noguchi was out of reach for us in the early 1970s,” says longtime California desert racer Dave Rymal. “At the time, I worked for Roehr Bros. in Burbank, who did all kinds of work on Yamahas and Hodakas, and Noguchi never crossed my plate at all. I left my AT-1 MX engine stock, put on a Roehr leading-link front end, and that’s the bike I raced. I don’t remember any Noguchi stuff out in the desert at all. I barely even remember the name from back in the day — if you didn’t see it in a magazine, at the track or in a store, you didn’t know about it.”

Jimmy Allison

“In 1974 I worked for a Yamaha dealer in Alamogordo, New Mexico, and we had a flat track north of town called La Luz Speedway,” Champion Motorsports founder Jimmy Allison recalls. “There was a group of racers and tuners using Noguchi parts on their Yamaha 125s, and I quite frequently ordered new pistons and cylinders from the distributor for them. I had never heard of Noguchi before then, so when someone first brought in one of the little single-ring pistons or a cylinder, I had to figure it out. Although we had some local tuners who were really good at developing their own techniques, there were a few particular guys who really liked the Noguchi stuff.

Barry Higgins

Barry Higgins is a former factory Ossa motocross racer, European GP veteran, Yankee development rider, and sponsored Noguchi racer in the Southeast during 1973. “Dirty Distributing gave me two 250 Noguchis before the first YZ250s were available here,” he recalls. “When I went to the first national in Louisiana, the Yamaha rep gave me an earful, because only their works guys were supposed to have YZs. But they were real YZs that Noguchi had obtained in Japan, kitted and then shipped here. By far they were the best and most competitive that first year. I could go to a local race, ride two classes and win probably $600 or $700, which was a lot of money. One time, in North Little Rock, Arkansas, the Jaycees put up a $5,000 purse for 125, 250, 500 and Trophy Dash. I won all three classes I raced and went home with $3,400 or $3,500. That’s more than I would make riding a national.”

Higgins worked on his own bikes and became quite familiar with Noguchi parts. “The cylinders looked like YZ cylinders but had different porting,” he states. “They were chrome bore prior to Nikasil. The heads were different and the pipes and silencers were handmade from cones. Later on, some of the pipes were hydroformed or stamped and then welded up. The Japanese were good copiers and they made what they copied a little better. The quality of the Noguchi stuff was really good.”

Curt Lange

Curt and Jared Lange are a father-son vintage motocross team in Tulare, California, and have campaigned a Noguchi-Yamaha 125 engine in a Maico frame for years. “The Noguchi kits weren’t meant for the guy in the novice class,” Curt recalls. “They were above the normal YZ and underneath what was available to the factory guys. You could take a stock YZ cylinder and make it faster, but Noguchi also did a good job. The intake port was bigger, and the transfers and exhaust port were also higher. Any Yamaha shop could order a cylinder back in the day, and we used to buy their low pipes — they were great.

“Statements of poor quality or failures are unlikely to be true,” Lange says. “People blow bikes up because they are not set up right, and if you were smart enough to break it in, that took a lot of error out of the equation. The Noguchi cylinders will just about never wear out if you keep dirt out of them. Jared has been riding his bike almost 10 years — I would put a piston and ring in it once a year, and only recently replaced the clutch.”

No U.S. Yamaha connection

The above statements perfectly explain the window that Noguchi — through Dirty Distributing in America — saw as viable, and they were right to pursue it: Bolt-on parts to upgrade the performance of bargain-priced Japanese motocross bikes. This worked for Noguchi and its customers for a time. But it didn’t get the attention of Yamaha.

When I rang various long-term Yamaha contacts, there wasn’t much recognition of Noguchi or its componentry, other than it had existed. This is likely because Yamaha had its own line of GYT parts for public consumption since the early 1960s, and more importantly for its own racing interests, produced special “OW” prototype motocrossers in Japan and exported them for team use.

Ed Burke was a Yamaha product planner responsible for bikes like the AT-1 and RT-1 Enduros. “I was aware of Noguchi, but mostly the fact that it existed in Japan,” he says. “I don’t know that I was aware of when it came into the United States.”

“During my time at YMUS (1972-1973 and 1977-1989) we never tested nor used any Noguchi parts or bikes,” says former Yamaha manager Kenny Clark. “I have no knowledge of how good or bad the Noguchi products were, and I also know of no Yamaha factory connection to Noguchi. We raced Yamaha works bikes up until the AMA rule changes required using ‘production bikes.'”

Keith McCarty joined Yamaha in 1977 as Bob Hannah’s mechanic and later became motocross development supervisor and then division manager. “Yamaha already had their GYT parts, which were available through dealers, and our race bikes had chrome cylinders almost from the beginning,” he says. “Sometime after that, Noguchi, as a private team, started making castings and doing their own machining internally. I never tested any of their parts or looked at them for racing — everything that we got was affiliated with Yamaha.”

Right in the middle

Undoubtedly, Yamaha’s own works bikes were miles above what a production MX or YZ could deliver. When privateers saw them at the track or in the magazines, their longing was natural — even though they couldn’t have one. And so, occupying the vibrant, wistful and fervent space between real works bikes and the showroom-stockers, for a time Noguchi found its place. “Win on Sunday, sell on Monday,” an adage used in car racing, worked at motorcycle parts counters too. Except with bike dealers closed on Mondays, for Noguchi it became “Win on Sunday, sell on Tuesday.” Well, whatever works! MC

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