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Memorable Motorcycle: Yamaha TZ750A

Monday, April 21, 2014
The law of unintended consequences is one which always defeats legislators throughout the world – and in whatever sphere they operate.

Gene Romero on the TZ750 at Laguna Seca.
Gene Romero on the TZ750 at Laguna Seca.
In 1972, the AMA was becoming discomforted – and you can translate that into the vernacular to know how they were really feeling – about the way things were going in the Grand National Championship.

BSA/Triumph had started the serious rot by turning up with factory bikes which, except for a few engine castings, were full on factory racers. Not that Honda was any less guilty with its CB750 race kits which transformed a refined, but sedate, 750cc racer into a full on GP bike.

To the AMA, the answer was simple and obvious. Introduce a straightforward rule which said that if a bike was going to be raced in the National Championship there had to be 200 examples made. Now, the playing field would be completely level once more and, most importantly, Harley-Davidson would be able to re-join the major league.

In this golden period for American motorcycle sport the one race to win in the American calendar was Daytona and initially, Yamaha was at a huge disadvantage at the Florida race track. This was only ameliorated by the tri oval’s tire-shredding, high-speed banking. Suzuki and Kawasaki both had large capacity two-strokes which readily converted to race machines to meet the new regulations – but these bikes simply destroyed tires.

Not having a large capacity two-stroke in its road bike range, Yamaha could only field its 350cc twin-cylinder racer but this was good enough to win the “200” in 1972 and 1973. However, the writing was well and truly on the wall. When the tire problem was solved then the game would be up for 350s at Daytona.

What the AMA didn’t reckon with was a manufacturer actually mass producing a GP bike but this is precisely what Yamaha did with the TZ750. This would be no converted road bike but a full on race machine from front wheel to back.

To understand Yamaha’s decision, we have to go a fair way back into the history of motorcycle racing. In the heady days of Yamaha’s world-wide expansion, its flagship bikes were always twin-cylinder two-strokes. Yamaha’s management always liked to link racing very directly to its road machines and so right from the TD1 in 1962, they sold twin-cylinder race bikes which the well-connected privateer could purchase. These were true over-the-counter racers and you simply put gas in the tank and headed for the track.

In another example of the law of unintended consequences, the FIM decided to simplify racing in 1967 by limiting all 250cc racers to only two cylinders and six speeds. The effect was immediate and dramatic. Instead of exotic six-cylinder Hondas and four-cylinder Yamahas and Suzukis the class became as dull as the CEO’s speech at the office Christmas party with every bike sounding and looking the same.

Clearly, spectator attendance plummeted and GP road racing fell into a trough.

Factory interest was minimal too and this allowed some really odd things to happen. Ex-Yamaha works rider Phil Read took a completely standard, but tuned, 1971 Yamaha engine to British motocross frame builder Eric Cheney, with the instruction to make a chassis which handled.

Eric had never built a road racing frame before but didn’t think that the job was too difficult and set to with his artist’s eye, a tube bender and a welding torch. Three days later, the Cheney chassis was finished and it was good enough for Read to win the 1971 World Championship.

As well as the 250cc Twins Yamaha also made some lovely 350cc Twins and these too were freely available to well-heeled privateers.

When Yamaha decided that it would start taking racing seriously again, it did so with a 500cc, four-cylinder bike which was built for the “Flying Finn” Jarno Sarineen.

Tragically, Jarno was killed at Monza in 1973 and this was an immense blow to Yamaha which had really taken the charismatic Finn to their corporate heart.

However, before he died Jarno had won two 500cc GPs on the OW20. The inspiration for the 500cc Four came from Yamaha’s GL750 road bike – an across the frame, four-cylinder two-stroke which was displayed at the Tokyo and Paris shows but never made it into production.

The instrumentation is basic on the TZ750.
A fabulous name on the fairing of this TZ750.
(Above) The instrumentation is basic on the TZ750. (Below) A fabulous name on the fairing of this TZ750.
The engine of the OW20 was both simple and elegant. It was not, as is now widely reported, a pair of Yamaha’s existing 250cc Twins linked together but was very much a new design – although drawing heavily on the experience the factory had with Twins.

The Twins were linked together with a central gear – an idea that had been around for decades. This gave a 500cc four-cylinder bike with a lot of power.

To address the problem of 80 horsepower spinning the rear wheel when the power kicked in, Yamaha took the reed valve technology from its world championship motocross experience. The reed valves enabled much bigger bore carburetors to be used than in a conventional engine and also softened the power delivery.

If a pair of 250s could be harnessed together to make a 500, then why not up the game with two 350s? There wasn’t a reason why not and Yamaha had a further incentive in the arrival of one of the world’s greatest motorcycle racers in the form of Giacomo Agostini.

Ago desperately needed a big bike for Formula 750 races – and Yamaha needed to win Daytona which, in the early 1970s, was considered to be one of the most important international races in the calendar.

Ago came directly from MV Agusta where small, neat and light were considered to be the three paths to greatness. Like many riders before and since, Giacomo asked for what he knew best and specified a 53.5 inch wheelbase. A bike like this – 1.5 inch shorter than a Manx Norton or Matchless G.50 – turned on a dime but was more than incredibly frisky in a straight line.

Initial tests of the new bike – code named OW19 – were not encouraging. The Japanese test riders got off the bike in a state of shock and with no desire to continue riding it. Yamaha’s savior turned out to be Australian Kel Carruthers – one of the most intelligent and perceptive riders of his generation.

Kel was not only a very fine racer, and a World Champion, but he had also ridden some of the best handling bikes of the era in the form of Manx Nortons and Aermacchis. He looked at the big Yam in horror and immediately asked for the swinging arm to be extended by three inches.

Carruthers remembers the test clearly: “Well, the problem was the thing used to just shake its head at any speed over 160 mph. Incredible tankslappers! I mean it was scary...

“Basically it was too short. We went back to the factory that night, cut through the swingarm, added a couple of inches and lengthened the wheelbase. 95% of the problem was gone right there, then we played with the suspension a bit and got it pretty good."

The core of the problem was that the OW19, now officially called the TZ750, made superbike power but was still very much a classic chassis. Disc brakes apart, a rider from 1955 would have looked at the Yamaha and found it familiar. For example, the tiny swinging arm was constructed from two thin steel pressings welded together and the frame was an equally light construction. This would have been fine for 50 hp – but when over 90 hp was being put through it things were very different.

Regardless of the bike’s shortcomings, Giacomo earned his considerable salary by winning the 1974 Daytona 200 and the TZ750 took its first steps to fame.

Not that things were straightforward. The TZ followed standard Yamaha thinking by having its four exhaust pipes running underneath the engine. This was fine on the Twins, where the pipes were widely separated, but was a disaster with the four-cylinder engines packing four pipes in a space suitable for two.

The front forks are flimsy for 175 mph.
The front forks are flimsy for 175 mph.
At 10,500 rpm, the exhaust pulses caused flexing in the expansion chambers and Agostini was very lucky to make it to the finish of Daytona.

It wasn’t a happy place in terms of handling either. As the 1974 season progressed, it was found that the retaining clips securing the front fork dampers could pop out, leaving the already flimsy forks with no damping at all. At this point, many owners of the $3600 TZ750 decided that they would be much better off on a 350 which had vice free, Grand Prix quality handling – rather than a desire to kill its rider.

Over the winter of 1974/75 Yamaha took the TZ from 694cc to a full 747cc and this is where the bike which features in this story comes into its own.

This TZ was originally allocated to Kenny Roberts and then came into the hands of Gene Romero. I must confess to being a Romero fan. As a baby journalist, I worked with Gene on a number of occasions and, at a time when riders were not PR trained or aware, Romero was kind, courteous and the complete professional. He was also a much, much better rider than he was sometimes given credit for and could have been a serious challenger for the 500cc World Championship.

In those days, qualifying for Daytona was a flat out lap of the 2.5 mile, steeply banked oval. It was a daunting task as Barry Sheene proved when his Dunlop tire gave up at 175 mph and he undertook the most famous high-side in motorcycle racing history.

Gene and the Yamaha were doing over 175 mph lap after lap and this was a seriously dangerous exercise.

Romero was, and is, a thoughtful racer and his race plan was, in his own words, “…to let the hot dogs wear themselves out.”

And there was a fine collection of the hottest of dogs in the form Kenny Roberts, Romero’s teammate in the Yamaha factory squad but riding the later and better handling Monoshock TZ; Giacomo Agostini on another factory Yamaha; Steve Baker; Steve McLaughlin and GP star Tepi Länsivuori . Every single one was a strong contender for a win.

Once Roberts got down to work he opened up a 15 second lead over Länsivuori until his clutch expired.

Länsivuori’s race ended when he dropped his Suzuki and the drama wasn’t over for Gene either. On lap 27, the TZ seized. Gene said: “I thought it was all over. I pulled in the clutch, coasted 50 yards and was ready to pull it onto the infield and park the bike when I decided to give it one more try.

“Everything seemed to work okay so I kept on going, but for the rest of the race I rode with two fingers on the clutch.”

Gene took the checkered flag, leading an astonishing 19 Yamahas home in the first 20 places. Truly, the TZ owned Daytona.

The TZ then passed through numerous hands, being raced in Britain and Ireland, but all the time with its history known.
Now, British auctioneers H&H are offering it for sale at their Imperial War Museum auction on April 24. The estimate for the bike is a serious $75,000 to $82,500 and then there is the 12% buyer’s premium on top of this. This will make the bike an $85,000 - $90,000 purchase which just goes to show the power of provenance and history when it comes to these exotic race machines.

For more information contact info@handh.co.uk
Memorable MC: Gene Romero TZ750A
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duc750ss   June 15, 2014 10:40 PM
Hello xfactory
You said your friend owns the Romero Daytona tz 750.
I am a very interested party in purchasing this bike if the owner
is interested in selling. I am a collector in las vegas nevada USA.
you can reach me at- mikei750@yahoo.com
malcyTz750   May 25, 2014 02:02 AM
xfactory, Love it, you can't play on my terms (ie someone with more than passing knowledge of the model in question), so you roll straight to the abuse. Sorry, abusing me doesn't degrade this knowledge or in anyway reinforce your argument. In fact it has just reinforced your obvious lack of knowledge. Blindness: Now that is any interesting one - Given that my "handle" is clearly identified yet you still get it wrong, may I suggest you would be the one better served by an eye test. Though, I can understand your anger, given the humiliation you obviously felt, given the big talk below, then being manifestly proven to have zero knowledge of the topic of TZ750's. Regarding being a UK resident. May I point out the word "assume" (I know it's a big word, one you may not understand), but never assume anything - otherwise you make an ASS out of U and ME (though, that joke may be a little subtle for you). Where I live is no matter (and is not the UK, but why it would matter I don't understand nor will it keep me awake at night), but let's just say that TZ750 were racing and winning here before Ago won at Daytona in 1974. If you read carefully below (and I stress you may want to do it mouthing the sylables), I say the "only obvious non original parts I can see are the shocks". Have you priced a set of the original shocks (which were so crap at the time most riders would not use them to stop doors slamming). Most were tossed from day one, but a set could be worth 1000 pounds sterling (ABOUT 2000 yankee pesos). When I sold my original TZ750 last year, I was able to provide a set to the new owner (along with the original flat sided exh pipes). Disc Carriers: because this internet thing is obviously new and your mother probably does not let you online for very long , check this link from the Yamaha parts book for a TZ750A http://www.yamahamotorsports.com/partviewer/default.aspx?ls=sport#/Yamaha/TZ750A_-_1974/FRONT_DISC_BRAKE-CALIPER/TZ750A_(1974_MOTORCYCLE)/FRONT_DISC_BRAKE-CALIPER_(TZ750A_-_1974). Note the carrier - is the same as the photo, but is also same as the XS650 and was used in 74 and 75 on the TZ750. 76 was different and 77 onwards was different again. Opinions: Little that was opinionated there, more facts, they are quite different things. If you'd like any more information on TZ750's, more than happy to help. That reminds me, have you owned, worked on or ridden one? You never did say....
xfactory   May 7, 2014 01:22 PM
Malady or what ever your friggin name is. YOU "R" "A" TOOL!!! I'm sure since you seem to be BLIND that you must be a kiddy ump right??? The disc carriers along with the shocks are NOT correct!!! I'd love to chit chat more with you but I have to go take a dump!!! And lastly as it seems you maybe from the UK or that soon to be new addition to the Muslum World order opinions are aresholes, everyone has one!!! =P
malcyTz750   May 2, 2014 12:07 AM
Xfactory. Sorry to bust your bubble, but you can't "fake" a TZ750 by taking another model and tarting it up (like say a 916 biposto to a 955 Corsa). I've rebuilt or built 3 TZ750's and have owned 2. My mate owns another 2 and I know most of the bikes in my country. So much of the key parts of the bike is pure to the 750 and used on nothing else. Cases, cylinders, heads, forks, hubs, frame, swing arm, yokes, tank, throttle grip, mastercylinder, exh pipes, even the fairing mounts are specific to the model and ONLY used on that model. The bike in the photos that you call a fake, while I can't quantify it's history, is one of the most factory original TZ750's I have seen since I sold my identical one last year. The only obvious non original parts I can see are the shocks. Okay the discs are drilled, whoopee. Those are the original style disc carriers, forks, calipers, yokes, handle bars, front mastercylinder, front fairing mount, frame, swing arm, cases cylinders, heads carbs, rear master cylinder resv, seat, tank, ipes, rims (note the rims did not match from the factory, I can tell you the part number that is supposed to be stamped on them if you like to "count rivets"). Brake lines, ignition coils (and the ign is even specific to these things), I could go on, but I wont. But before dissing a bike for sale like this, I'd suggest having a good knowledge of the model in question, before commenting on it's originality. Current sale price of similar models in the UK have been 36k sterling, without known provenance in the last 12 months. I can't comment on the Romero bit, but I know another bike that was purported to be the Romero twinshock bike, but the owner went quiet when this one was wheeled out a few years ago if I think it the same bike. What does that tell you? Maybe you should buy one. They are the violent, docile, scary fun bike to ride, all at the same time! Thanks and good night.
xfactory   April 28, 2014 02:23 PM
I recently found out that RAT is a part of the company selling the bike. Thus aaaaaaaaaaaaaaaaaaaaaaaall the dancing and prancing and trying to justify what is "obviously" a "fake"..!!!! A parts bin bike pieced together from bits from a by gone age. If it walks like a duck, smells like a duck it MUST BE A DUCK!!! Like they say on Shark Tank... I'm out!!!
ratatoskr   April 26, 2014 01:17 AM
Pictures can help but they aren't enough. Over several years a race machine might be modified in various ways, get fitted with different wheels or rotors or shocks or switches, sponsor decals or color schemes. Another bike in the same auction, a 1955 NSU Sportmax, was raced first by John Surtees and later by Mike Hailwood. It's been restored in Hailwood's colors, but does that mean it's no longer the bike that Surtees rode? The true and legal identity of a vehicle lies in its fundamental components - the parts that don't generally wear out. That's the numbered frame/chassis and maybe the engine block (although that might be changed between races, let alone over 40 years). But if only to prove it's not a fake you also need to prove its continuous history by looking at the paperwork accumulated over the years, like bills of sale, records of work done etc. With this Yamaha there is apparently a file of evidence that traces the history of frame number 409000295 from 1974 to the present. It's been examined by reputable experts and they reckon its genuine. Of course in the end authenticity comes down to a judgement of all the available evidence, and every auction house advises buyers to look at everything before spending money. If you really think that letters written in 1975 by the likes of Kel Carruthers, Bill Smith and Kenny Roberts must be fakes, or that those guys are liars, then you won't buy it. Why you'd doubt them, I don't know. These guys prepared and/or raced this bike at international level. You think they didn't know what they were riding in the TT or the Ulster GP? I'd certainly have more confidence in them than I would in some anonymous guy's claim that his anonymous friend says he owns the real bike, unsupported by any evidence at all. In fact xfactory carefully avoided stating that Romero's bike hadn't gone to England and raced in all those Irish events, which would be easy enough to prove if his friend has owned it all along. More likely, on the balance of evidence offered so far, his friend owns a mock-up and has been pretending it's the Daytona winner for so long that he can't admit otherwise without looking like a jerk. A more interesting and serious question is how to define an "original" race bike or car when even factory teams regularly modify, cannibalize, repair, discard or swap components from one machine to another over several seasons, then sell it to a lesser team, who eventually pass it on to someone else further down the ranks. It's a wonder anything survives, which is why people want good provenance. There was a case a few years ago when two 1950s D Type Jaguars were both claimed to be a Le Mans winner, because both contained parts of the actual winning car. They looked identical in pictures. But which one was "genuine"? Jim Clark's 1965 Indy-winning Lotus 38 was wheeled straight into a museum and stayed there until it was rebuilt a few years ago to run at Goodwood, England. Is it no longer "genuine" because it has new axles, wheels, tires, bearings, pistons, gas tanks, fuel lines, paint etc etc etc? If you restore a machine with a long history, which period do you recreate? How do you decide? Don't forget Romero's Yamaha had already been modified even before he rode it at Daytona! Would it be "less original" if it was restored to match its appearance at the '75 TT or the Ulster GP? Does it become "more original" again if you repaint Romero's name, and find some 40 year old magnesium wheels and some shocks and rotors from a different bike, just to make it look more like the pictures taken at Daytona? Even if a race machine does somehow survive in perfectly "original" condition, could you ride it after 40 years without worrying some old part will break and kill you? Does restoring it to running condition destroy its authenticity? Or is its value only preserved by keeping it in a museum, or friend's garage, consuming more wax then gas? Of course some people never have to make such decisions. So here's a question. If someone gave you this Yamaha as a gift, exactly as it stands, what would you do with it?
ratatoskr   April 23, 2014 06:36 PM
Yeah - the motor and frame that Gene Romero had, at Daytona. With documented numbers and continuous history supported by correspondence from Kenny Roberts, among others. As you have failed again and again to offer the tiniest shred of evidence to the contrary, I can only conclude that you are talking out of your friend's ass.
xfactory   April 23, 2014 04:01 PM
Rat you FAIL judging historical vehicles. This is just a motor and frame that someone had. The rest of the bike was pieced together from spare parts. Not authentic. Not original enough to warrant what they want for it. Just a run of the mill 750. And it's pretty obvious you can't tell the difference.... like Ralph Williams said, there's an ass for every seat! Some ass will buy this and be taken to the cleaners....
ratatoskr   April 23, 2014 12:37 PM
xfactory, what I don't understand is why Yamaha would mothball a race-winning bike early in the '75 season. Your photos only show what the bike looked like at Daytona in March '75 (if that's when they were taken). If as claimed it continued to race, with different riders and different (non-factory) owners, it's sure to have been modified, altered and repaired over the years. That's what happens to race bikes - teams aren't concerned with preserving a period appearance. If the rims are cracked, you change them. If the brakes aren't strong enough you drill or replace the rotors. Etc. Nothing in the sale catalog claims the bike is just as it was in the winners circle at Daytona, instead it goes into detail about how it has been raced (and restored) in the intervening years. That history doesn't make it a different bike, or a fraud, or a mock-up (quite the opposite). But if someone else owns a similar looking machine that they've been passing off as the genuine article, they might well be sore when the real thing appears at a public auction. In fact I suspect it's your friend's bike that is the "mock up", because no race bike would remain in the same 'period' condition for 40 years unless it's been kept as some kind of museum piece, but you've offered no evidence for that either. I don't know who the seller is and I don't really care. But he claims to have a comprehensive history file, checked by reputable people and open to scrutiny by potential buyers, and he quotes a frame number that ultimately defines the bike's true identity. You've pretty much dismissed all this provenance out of hand and come up with just a couple 40-year old photos and a lot of unsupported allegations and nonsensical opinion. Not very convincing.
xfactory   April 23, 2014 11:19 AM
anda 2: http://4.bp.blogspot.com/_ao3uUOVmQo8/SXWmkYVLEhI/AAAAAAAAJ6g/EQPsYw7KdAE/s400/gene+romero+daytona+1975.jpg
xfactory   April 23, 2014 11:18 AM
Hey RAT did I say that?? Let me try this again: http://www.motorcyclemuseum.org/halloffame/detail.aspx?RacerID=89
ratatoskr   April 23, 2014 10:39 AM
xfactory, you're saying Yamaha's works team didn't take the Daytona-winning bike to England to contest the transatlantic match series, Bill Smith didn't race it in the '75 TT, Kenny Roberts didn't ride it in the '75 Ulster GP and Adrian Craig didn't use it to win the '76 and '77 Irish Championships?
xfactory   April 23, 2014 10:38 AM
Here are 2 more pics showing that this so called Gene Romero bike is a fraud. Gene's bike not only had mags ( I believe they were Shelby mags). but look at the front disks and carriers? I have no idea what are on this mock up bike but they are NOT Yamaha parts!!! This bike is a hodgepodge of parts made to resemble a bike of history and if you know anything about the real bike this mock up isn't it!! http://www.motorcyclemuseum.org/halloffame/detail.aspx?RacerID=89 http://4.bp.blogspot.com/_ao3uUOVmQo8/SXWmkYVLEhI/AAAAAAAAJ6g/EQPsYw7KdAE/s400/gene+romero+daytona+1975.jpg
xfactory   April 22, 2014 03:56 PM
In response to HandHclassics. Maybe you bought a motor and frame but the rear shocks, the paint the front forks, the front disks and on and on are not original. All this is is a 750 lookalike made from parts. These are done all the time. And to pay 85 grand when the provenance is not really there, R U SERIOUS??? Anyone who pays this type of money for a twin shock 750 that isn't even all original deserves to get taken!!! I could care less about your authentication of the motor etc. If this bike was unmolested and original that would be one thing. BUT IT ISN'T PERIOD!! And the fact that your selling it as it is shows all that you are not legit. Would Wayne Carini buy a mock up??? HELL NO!!!! He wants it all original because as soon as it's been messed with it kills the value. A good friend of mine judges motorcycle shows all over the place and has been for years. He looked at this bike and then looked at older pictures and he tore this thing apart!!! He even pointed out things I hadn't caught. Like I said it's a wanna be. Nothing special here....
HandHclassics   April 22, 2014 08:55 AM
In response to xfactory - H&H cannot investigate the provenance and history of every single lot consigned to our auctions. However, in this case considerable research was carried out on our behalf by George Beale, a highly respected authority in motorcycle racing circles. The evidence indicates that shortly after its Daytona victory in 1975 the TZ was purchased from Yamaha team manager Kel Carruthers by reputable motorcycle dealer and racer Bill Smith, of Chester, UK, who supplied a letter confirming its engine and chassis numbers. This is backed up by further research that supports the vendor's claims, and many more details of the machine's history are set out in the auction catalogue, which may be viewed at www.classic-auctions.com. Of course ex-competition machines have often led 'interesting lives' and it is quite possible that the rotors (for example) were drilled after the motorcycle passed from Yamaha to non-factory ownership. As ever, buyers should satisfy themselves prior to bidding as to the condition of each lot and should exercise and rely on their own judgement as to whether the lot accords with its description or not. To that end, H&H is happy to supply interested parties with copies of the letters and other paperwork provided by the vendor in support of his claims.
xfactory   April 21, 2014 06:30 PM
This is BS and you guys are quick in deleting my post I put up 2 hours ago!!! WTF happened to freedom of speech. Especially when it comes to BS. My friend bought Genes TZ750 and still has it! This is a bogus mock up. The real TZ does NOT have a on/off switch on the left clip-on! These are TZ rims!!! And Yamaha never drilled the rotors! OK let see how many seconds before you delete it!!!