1972 Yamaha R5 350
Engine: 347cc air-cooled 2-stroke parallel twin, 64mm x 54mm bore and stroke, 7.5:1 compression ratio, 36hp @ 7,000rpm (claimed, 1970 model)
Top speed: 100mph (claimed), 95.31mph (period test, 1970 model)
Carburetion: Two Mikuni VMSC 28mm
Transmission: 5-speed constant-mesh, left-foot shift, chain final drive
Electrics: 12v, AC generator, ignition points
Frame/wheelbase: Tubular double cradle frame/52.8in (1,341mm)
Suspension: Telescopic forks front, dual coil-over shocks rear
Brakes: 7.2in (183mm) TLS drum front, 7.2in (183mm) drum rear
Tires: 3 x 18in front, 3.5 x 18in rear
Weight (dry): 326lb (148kg)
Fuel capacity/MPG: 3.2 gal (12.1ltr)/34mpg (period test, 1970)
Price then/now: $739/$2,000-$7,000
By the late 1960s Yamaha’s production racers, the TD (250cc) and TR (350cc) were enjoying unparalleled success on racetracks around the world. But the racers’ street bike counterparts — Yamaha’s bread and butter consumer products — were showing their age.
Compared to other contemporary middleweight models on the market, bikes like Honda’s CB350 and Kawasaki’s Avenger A7 350, Yamaha’s DS6 (250cc) and R3 (350cc) models relied on 10-year-old technology to lure customers into dealer showrooms. No surprise, sales began to lag.
That was about to change in 1970 with the launch of two all-new models — the DS7 (250) and R5 (350). Beyond engine displacement, these new models were joined at the hip in many ways, sharing similar and updated platforms.
But when Yamaha Motor Corporation released those two models (the R5 in particular) the folks at headquarters in Hamamatsu, Japan, had no idea that the new roadsters — both powered by all-new air-cooled twin-cylinder 2-stroke engines — would have a lasting impact on amateur road racing in America. And the R5, in particular, did exactly that.
The R5’s engine, like the DS7’s, had horizontally split cases, a welcomed improvement over the R3’s vertically split lower-end cases. The top end was a new design, too, meant to deliver a wider power band than the R3’s. Wrote Cycle Guide’s editors for their January 1971 issue, “The new 350’s power spread is a good deal broader and as a result, the rider doesn’t spend nearly as much time shifting gears as he used to [with the R3].”
That was fine and dandy for the street crowd, but road racers weren’t concerned whether or not their race engines had broad power bands. Then as now they wanted horsepower any way they could get it. And lots of it, but in 1970 Yamaha claimed the same basic peak horsepower figures for the R5 as with the R3 — 36 horsepower for either model. So why, then, did the street-going R5 create such a stir among amateur road racers in America?
Because the R5 was a complete and balanced package; power delivery, braking prowess, and ride and handling meshed to create a bike that shined not only on the highways and byways of America, but on racetracks, too, where amateur club racers easily prepped their R5s for production-class road racing. And they did so with success, typically beating the other brands that vied for 350cc class dominance at the time. Southern California club racers, especially, filled their display cabinets with cheap trophies won racing their R5s. Young racers like Mike Devlin, Dick Fuller, Bob Crossman, John Lassak and Alan Gingerelli, to name a few, rode R5s to success during the early and mid 1970s.
Shorter stroke, reduced piston speed
New cylinder bore and stroke specs, coupled with reconfigured intake and transfer ports, accounted for most of that engine improvement. Gone was the R3’s 61mm x 59.6mm long-stroke cylinders in favor of the R5’s 64mm x 54mm jugs that equated to less piston speed at any given rpm. The wider bore offered increased piston-port area, and the addition of a fifth, or boost, port helped further direct the fuel charge centrally to the combustion area for more efficient ignition. The sum total helped expand the engine’s powerband without sacrificing peak horsepower. And the savvy production-class racers who understood 2-stroke tuning altered their engines’ port timing to gain even more power, but that’s a story for another time.
For now, know that the R5’s refined engine was cradled in a frame boasting its own road racing heritage. Based on the fabled Featherbed design that Norton perfected years before, the R5’s double-cradle frame took its DNA from Yamaha’s first-ever successful Grand Prix road racer, the RD56 that debuted on European racetracks in 1963. The following year Englishman Phil Read joined the factory team to race his RD56 to Yamaha’s first-ever Grand Prix World Championship. Little did Read know at the time that he, along with the entire factory team effort, was helping lay the groundwork for future TD and TR privateer race models as well as the R5 street bike that was to come six years later.
“Going around corners,” wrote Cycle Guide’s editors about the R5, “the chassis is absolutely rock steady. So much so, that the rider gets a distinct impression that the wheels are running in a slot,” also citing that the swingarm pivot area had been “greatly beefed up,” further accounting for that rock-steady handling.
Cycle World, buoyed by editor Ivan Wager’s road race experience, was more succinct in its praise for the R5’s chassis. “This capable frame design,” they wrote in the June 1970 issue, “is the direct result of knowledge gained from racing, with the benefit passed on to the consumer. Rigidity is one of the R5’s virtues.”
Interestingly, Cycle’s editors were less impressed with the R5’s handling, stating in the December 1970 issue’s 350cc middleweight shootout (pitting the R5, Avenger, CB350, Bridgestone GTR 350, Suzuki T350, and the thoroughly outgunned Harley-Davidson Sprint SS 350 against one another) that the “front forks continued to oscillate through some of Lime Rock’s [Raceway] turns.” Soon enough, though, amateur road racers discovered that by replacing stock fork oil with a slightly heavier aftermarket mixture, and by replacing the stock rear shock absorbers with aftermarket suspenders from companies like Koni or S&W Engineered Products, along with fresh Dunlop K81 tires front and rear, the R5 rewarded its rider with world-class handling on the racetrack, thank you. Much like Read’s RD56 must have performed in 1964.
The 347cc air-cooled 2-stroke parallel twin makes 36 horsepower at 7,00rpm, good for a top speed of about 95.
Whoa, Nellie!
Other than what was on Honda’s CB750, motorcycle disc brakes in 1970 were pretty much a thing of the future; most consumer bikes at the time were equipped with cable-operated expanding-shoe drum brakes for whoa-ing and slowing. Yamaha’s R5 was no different, relying on 7.2-inch-diameter drum brakes front (double-leading shoes) and rear (single-leading). Cycle World praised the R5’s brakes in its June 1970 issue, stating, “The R5’s smooth, progressive, grab-free [brakes] show only a slight tendency to fade under repeated use.”
Meanwhile at Cycle Guide the editors wrote: “The braking department was kind of ho-hum … it never felt as though there was a surplus of stopping power.”
And Cycle’s Jess Thomas wrote, “I had to pull extremely hard on the Yamaha brake, but the feeling of control was reassuring. The cable required adjusting a lot after the first stop, but sensitivity remained good. The stops were all straight, with no tendency to swerve or lock suddenly.” There you have it, three magazines, three different opinions, but we can check back with the racers at the track to see that, even with the coming of the RD350 and its front disc brake by 1973, some of the stubborn Southern California club racers stuck with their R5’s front drum brakes, and were rewarded with considerable success.
Three-year run
Indeed, ultimately it was the RD350 that helped put the R5 out to pasture. A 6-speed transmission, reed-valve cylinders for improved low-end response and that trusty (yet heavier) front disc brake combined for a much better and congenial street bike — and racer. One thing that didn’t change, however, was the snappy handling because like the R5, the RD350’s potent little engine was straddled by one of the best frames on the market at the time.
And it was the R5/RD350’s road race prowess that helped a wide-eyed teenager from Thousand Oaks, California, change his allegiance from motocross to road racing in 1977. Thad Wolff was a 17-year-old motocross racer when his friend and racing cohort, Bryan Cathey, read a Cycle magazine article about another young SoCal racer, Scott Clough, competing and winning at local road race tracks aboard his RD350. “We can do that,” Cathey suggested.
Before he knew it, Wolff found himself standing in Cycle magazine’s front lobby, which happened to have its editorial offices just a stone’s throw from Wolff’s home. That also happened shortly after editor Cook Neilson won the 1977 Daytona Superbike race.
“I’m not sure what I was thinking,” recalls a more mature and worldly Thad Wolff today. “I asked to see Cook,” he continues, “and guess what? He actually came out, introduced himself, and then invited me to his office.” A brief Q&A session followed, prompting the ever-so-patient Neilson to halt their discussion while he reached into his desk’s bottom drawer, reappearing with an AFM (American Federation of Motorcyclists, the leading amateur road racing club in the country at the time) rule book. He tossed the book, no doubt its cover marred with greasy fingerprints and the pages inside dog-eared and highlighted for quick reference, into Wolff’s surprised hands.
“Here,” began the Daytona Superbike winner, “read this.” He added sternly, “And be sure to wire the engine’s drain plug.”
Thad Wolff riding his Yamaha R5.
“He told me more than once to do that [wire the drain plug],” Wolff recalls. “He probably didn’t want me to be the guy whose drain plug popped out and oiled the track right in front of him.”
Wolff read that rule book and applied his newfound knowledge to an aging 1972 R5 that he purchased on the cheap. Next, young Wolff applied his talents at the racetrack to ultimately win the 410cc Production Class Championship with his much-modified R5 (see RD350 engine, transmission and disc brake upgrade reference prior) in 1979. The following year Cycle’s managing editor, Phil Schilling, connected Wolff with Neil Sorensen from Minnesota, and the pair invested in a brand-new Yamaha TZ250 for Wolff to ride in the 1980 AMA Novice class. Wolff won his first race on the bike, and kept on winning to wrap up the championship. He advanced to the Expert class, competing in AMA Superbike (Suzuki GS1000) and Formula 1 (riding an aging Suzuki RG500), finishing the 1982 Superbike season sixth in championship points and fourth overall in the Formula 1 class.
A footnote about his pro racing career: To raise funds for that TZ250, young (but growing older … and wiser) Wolff sold his 1972 R5-cum-RD350 production-class racer. Which brings us to the gold-and-black, all-original 1972 bike featured here that belongs to — you guessed it — Thad Wolff!
It followed me home — really
“I spotted it in a used car lot,” begins Wolff. “The bike was for sale, and in really clean and complete condition,” he added, right down to its original tires. That was in the autumn of 1993, and by then Wolff had well established himself as a member of the motorcycle industry, posing and riding as a professional photo model for magazine road tests and manufacturers’ advertisements. He also served double-duty transporting bikes to photo locations. It was during one of those outings that he spotted the R5, a bike in surprisingly original condition.
“I was able to get back to the lot after delivering the bikes and I bought it [the R5].” He pauses to let that sink in, and then: “I wanted that SOB real bad!”
He rode the bike, off and on, for several years before parking it in his storage shed where it idly sat until he and I got to talking one day — him doing most of the talking — about that bike. I told him that we must photograph his R5, and that was all there was to it. After much prompting and bullying on my part, he finally relented, fetching the bike — original tires, its acquired patina and all — to see the light of day. That’s when the fireworks really began after a thorough cleaning.
Thad Wolff and his very original 1972 Yamaha R5, which even still wears its original tires.
Smoke gets in your eyes
“It fired up right away,” recounts a proud, older and wiser Thad Wolff. “Second kick. And when it did fire up the garage filled with smoke. Of course, beforehand I forgot to shut the door leading into the house, so the whole place filled with 2-stroke smoke.” His story gets better: “And guess who comes home just then?” Yep, The Boss, aka Mrs. Jody Wolff, initially greeted by a blaring smoke detector, followed by billowing blue smoke. “She thought the house was on fire, but she soon realized it was 2-stroke smoke, so she figured out that it had something to do with me and my bikes instead,” Wolff says so sheepishly today. As most of us diehard gearheads have come to realize, it pays to have an understanding and tolerant — and very patient — spouse.
Wolff suspects that his consequential oil boom had something to do with the oil injector pump sticking open and, over the years, allowing oil to seep into the engine’s nether regions. In any case, he rectified the problem and as you can see by the riding shots, the old R5 runs smoothly down the road. And, in certain terms, it preserves the dreams and aspirations of countless aspiring and wannabe road racers alike. Because, regardless of what race bikes that came before or after Yamaha’s R5, there’s no taking away the impact that this model had on the sport of motorcycle road racing at all levels.
And that’s something that the Cycle editors realized way back in 1970 from their middleweight shoot-out. Because when all was said and done, the editors proclaimed: “And we proudly present you with a winner: Yamaha’s brilliant R-5, the best production street 350 in the world.”
Truly, the R5 was the bike that successfully bridged the gap between the racetrack and the public roads of America for Yamaha Motor Corporation. In the process the R5 etched a legacy that will never be taken away by future models from the motorcycle company with the tuning fork logo. MC
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As a high-schooler in 1975 I purchased my second bike, a stock R5C. Steeped in contempt for all things Harley and Honda, I went in search of prey, rarely finding any, to my chagrin. I saved enough for K81's, a bore job, and a Bell Star. A buddy with a brand new XS360 accompanied me on my first foray to the mountains for a camping trip. The R5 became a bit sluggish up there, but I attempted no adjustments. On a beer run to the valley I engaged a CB450 in a twenty-mile jaw-clenching road race, perhaps the most foolish fun I've ever had. I was able to take him in a tight turn, but spent most of the time looking at his taillight. I came away with a sore jaw and a grudging respect for Hondas and their riders.
Scott...Glad that you're the "proud owner" of a highly modified R5B, but I was referring to "stock" R5s vs "stock" Honda CB-350s I raced both AAMRR and ERA/WERA 1973-1982 and saw a lot of RD-350s and 400s and a very few R5s (all of which had been converted to TR-3 road racer specs for "Cafe" and "Modified Production" classes). By 1977, yes, at many meetings that I attended (Summit Point, Rockingham, Charlotte Motor Speedway...VIR closed in 1974) almost 50% of the bikes that showed up were RDs, but almost all of them were RD-400s in the Production class, not RD-350s. While I suppose that you could shift lines with the RD more readily than a CB-350, I would have to tell you that I passed more than one RD350 by changing lines mid-corner on Honda CB500 and 550 fours (with Koni shocks) by knowing that I could rely on the Honda's steady handling (particularly at a bumpy track like VIR or Summit Point) and superior lean clearance (as compared to a stock-pegged RD350). I would also note that after shifting that line, as you suggest, the RD rider still had to contend with a front-end light machine that would want to run wide as he/she applied the throttle. Apparently Yamaha was also aware of this shortcoming as when they designed the 400, they moved the engine forward in the frame to put more weight on the front wheel, which steadied up their handling. The RD-400s also had their pegs mounted differently, eliminating the under-the-mufflers peg support of the RD350 for improved lean clearance. And certainly a CB-350F is much slower than the RD 350 or 400 or your tricked- out R5...they were also slower than a CB-350 twin! I would note; however, that I saw CB-400Fs during 1975-76 that consistently placed in the top five in ERA/WERA Production and Modified Production classes and saw 1978 CB-500T Hawks win the Production class against the vaunted Yamahas. I would also note that Peter Egan, a writer for "Cycle" magazine, won his AFM class in California with a 1978 CB-400T Hawk before he became employed by "Cycle." As for your comment that "...R5s handle like the GP racers they are directly derived from," one of the most successful Yamaha 350 racers of the time, the Don Vesco-tuned TR ridden by Kel Carruthers, had its engine moved forward in the frame to put more weight on the front wheel. Most of the other Yamaha racers of the day had similarly relocated engines. Back in those days, a bike didn't really handle on a racetrack without both wheels in firm contact with terra firma, particularly in a corner. In fact, even today's MotoGP bikes keep both wheels on the ground in corners... mid-corner wheelies are not fun!! I would also note that Yamaha's real GP bikes of the era, the RD-56 and RD05A, were hardly paragons of good handling. In fact, Mike Hailwood beat them regularly on less powerful, but steadier handling Hondas.
Rhip ...I knew two other R5B owners in college. One, a stocker, was slightly quicker than mine until I put a K&N filter in my airbox and Yamaha accessory check valves in the my oil injection lines. They were then pretty much identical. The other R5B had expansion chambers on it and was a bit faster than the stockers, and even more wheelie prone. I also worked in a Yamaha shop one summer and got to ride R5Bs, R5Cs and RD-350s, so don't try to tell me about how the R5 was "all that. One of the shop's mechanics rode a CB-350 (yes...while working at a Yamaha shop!) and beat me regularly that summer. The R5C models, with the seamless "RD-style" mufflers were a little quicker and cleaner running than the R5s and R5Bs. I remember when Cycle's 350 Comparo came out (I'm an "old guy") and I based my initial thinking on their results...which were a crock of crap. Cycle World also tested the R5 and the CB-350K3 and the R5's best in the 1/4 mile was 15.46 seconds at 81.08 mph. The CB-350K4's best was 15.17 seconds at 83.87 mph. I even switched off with a buddy who had just beaten me on his Honda CB-350K2 (1970) and beat my own bike with my buddy on my R5. My bike had "no" issues...you just were racing "flower sniffers" on the Hondas. As an aside, Cycle World only got a 15.48 second, 82.19 mph 1/4 mile out of a Suzuki T-350 Rebel. And please spare me the whole "handling thing," I raced Production class bikes with AAMRR and ERA/WERA for about 9 years (1973-1982). On anything less than a perfectly paved racetrack (the complete opposite of your typical North Carolina back road), the Honda was much steadier, a lot more predictable and had competitive lean clearance. Btw... both Cycle and Cycle World got low-14s out of 5-speed CB-450s in the 1/4 mile.
My R5 was my last road bike with front drum brakes. It would be the bike for which I made a discovery that, although decades late, I still use when it comes to drum brakes. I had just gotten out of a right wrist cast and was too weak to slow my R5 for safe riding. Desperate, I pondered how to improve the brake. Noting the much smaller pad size of disc brakes and remembering my Matchless scrambler easily out braking any other British bike despite having the smallest lining area, I ground away the center third of my lining, leaving two pads, fore and aft. i speculated there would be a wedging action and evidently I was right. The brake was significantly stronger. All these decades later I have never heard of another using this simple idea.
I am the proud owner of an R5B, that I have owned since 1976. The original owner was a Yamaha mechanic and WERA racer. Mine has been retrofitted with a 6 speed and a RD400 front end. Twitchy and responsive compared to a Honda, and other two wheeled trucks yes but, a solid handling bike. Not only would they hold a line, you could change your line mid turn, (to avoid the Honda). Once the shocks were swapped, and the fork sorted there are no real issues for a skilled, aggressive, and deliberate rider. In the 70's, any and all bikes required aftermarket shocks and fork tuning, including Yamahas. Rear end biased but, that is the way you would want a 300 pound two stroke to be. I still evaluate wheelbase of other bikes in comparison to the R5, 52 inches! By 1977 about half the bikes at a WERA race were either RDs or R5s, and they took trophy's all the way up into the fastest classes. The only CB 350 / 400 around were easy to find. Just wait for all the Yamahas to go by! I have both a CB350F and the R5. The CB is much slower, much heavier, and handles like a truck in comparison. Really, R5s handle like the GP racers they are directly derived from, Hondas CBs definitely do not. Of course my tuned R5 is faster than stock but, it would outrun pre 79 stock CB750s, and was a good race for some Harleys as long as I had a passenger.
JDunne, I disagree. I owned a '70 and a '72 R5, and NEVER got beat by a CB350. Check out the 1970 Cycle comparison test - the A-7 was slightly quicker than the R5 (14.35 vs.14.67), but the CB came in at 15.16, which sounds about right. That time is quicker than any Triumph Daytona (great bike) or CB 450. It also handled better than the Honda. Your bike must have had some issues.
my god still have my bought new early rd250 in 2020. I was 17 at time(do the math).it would go 107 as indicated on speedo.as I got older I bought new 1977 kz1000(name superbike cycle mag) turned my guns on the rd and hot rodded it as a mechanic does.new rd350 barrels,ported by an old man that did dirt bikes(now a'm the old man),cut rd250 heads on lathe to clear 350 pistons(spark plug is 1/4" closer to piston on 250),cced heads,bought tz350 pipes from yamaha.bike had lost all low end torque(pipes) but made ungodly power from 6 to 12500.recently semi restored and made it run,what a sound.have ms,no more riding for me Marty nj
Sure the Yamaha R-5 was a "bridge"....and I've got a bridge in Brooklyn that my family owns and that I'd like to sell! I owned and rode a 1971 R-5B (orange & white gas tank) during 1972-73, putting about 20K miles on it. While Cycle magazine had declared it the "winner" in a 1970 350cc comparison test and Yamaha claimed "race-bred" power and handling, I very quickly found out that a Honda CB-350 would outrun it, particularly if you didn't put a new set of plugs in the R-5 immediately before the run. At first I was very frustrated and bewildered about this situation, but I later came across the Cycle World tests of both bikes and learned that their CB-350 had been almost 1/2 second quicker in the 1/4 mile than the R-5 (15.1 vs 15.5 sec.). I also got the chance to ride several CB-350s (as well as other R-5s and, later, the RD-350s) and found that they were easier to get off the line than the R-5 and covered ground much faster than their engine note would otherwise indicate (the R-5 always sounded fast...it just simply wasn't as fast as it sounded). The idea that a stock R-5 would run as fast as a bike "twice its size" as indicated by many propagandists (or old owners with "rose-colored glasses) is quite simply preposterous and mythical. While an R-5 could, possibly, give a single-carb, 4-spd Triumph or BSA 500 a hard time, it would simply be an appetizer for a Triumph Daytona or CB-450 with a 5-spd box. As well, the R-5's tranny ratios didn't help as there were significant gaps between 1st and 2nd and 4th and 5th gears. One had to wind 1st gear pretty tight to avoid bogging when you shifted into 2nd (despite the R-5's relatively wide power band for a piston-port engine) and you could get caught in city traffic situations "between gears" (1st being too low, while 2nd was a bit too high). As well, 4th was useless as a passing gear above 60-65 mph (it needed the "bridge" of an RD's 6-spd gearbox). The handling was also less than stellar, being that the R-5 had too little weight on the front wheel (at least with the stock handlebars), a short wheelbase and quick steering...can you spell t-w-i-t-c-h-y? While the light front-end enabled you to pull easy (and many times unintentional) wheelies (reinforcing the illusion of speed and power), it also made the steering and handling rather dicey coming out of corners, particularly on a road with slow, tight curves (just the kind of road where you might think that you could catch that CB-450 or Triumph Daytona 500 that had just blown you away on acceleration). And like most 2-strokes of the period, points and plug life were also issues...aggravated by the fact that Yamaha didn't have any check-valves in their Autolube system (Bridgestone, Kawasaki and Suzuki all had them) which contributed to over-oiling, particularly at idle. I eventually gave the R-5 to my Dad and purchased a left-over '72 Honda CB-500 Four, riding and racing it with AAMRR and WERA for 3 years and 30k street miles and being much happier. The only "R-5" that could run with it was disqualified for having TR-3 cylinders (and may've had a 6-spd box too). I will give Yamaha credit for one thing; however, "The Sow's Ear to Silk Purse" award for converting the R-5 into the 1973 RD-350...which corrected almost all of the R-5's shortcomings (except for plug fouling)....but was really no quicker than a 1969 Kawasaki A-7 350. I will forever wish that I had bitten the bullet and bought a Bridgestone 350 GTR instead of the R-5...6-spds (no need for a "bridge"), rotary valves (more power and a wider power band), rubber-mounted engine (no vibration), more weight on the front wheel and a much better highway bike for running home from college on weekends. 'Course the CB-500 Four addressed all of those issues...plus!!
Thanks for this. My first bike was a 1972 R5C. I recently found another, currently awaiting restoration in my garage. Thanks!
You certainly pushed my fun-button with the RD 350 story. Like many of the day, we were mid-pack endurance-racers with an RD 250 and its huge reliability and killer power, with added pipes, or course. Like many, it never spit any of us off even when the tires were showing cord and even when we probably deserved it. I do wonder about what happened to Ivan Wagar. I recall him telling us one time about him racing a Moto Guzzi in the 1950s and why the factory purposely declined to paint their dustbin fairings of the period. Does anybody remember why that was, or what ever happened to Ivan? Thanks for the continued excellent contributions. Gary W.