Yamaha TZ750 – The Holy Grail of Two Stroke Racers

The Yamaha TZ750 is up there with being one of the most influential motorcycles in history. 

From the foundation of the design to its racing and record setting achievements, it had an impact in motorcycle culture that most engineers and designers can only dream of. 

One of the big reasons Yamaha built the TZ750 was to compete in the Formula 750 class throughout the 1970’s. 

The other big Japanese manufacturers were all equipped with large capacity superbikes and it was an area in which Yamaha were lacking. 

Honda’s CB750, the Suzuki GT750 and the Kawasaki H2 750 were dominating not only the streets but in racing too and Yamaha had nothing to compete with.

The XS650 was their closest offering and it had nothing on the competition, it was time to step it up a level.

In 1971 Yamaha displayed a mock-up of a four-cylinder, two-stroke roadster called the GL750. It was on show at the Tokyo motorcycle show and later the Paris show. 

While the GL750 was nothing more than a fuel-injected two-stroke shoved into a XS650 chassis, it made a statement, Yamaha were gearing up for something big. 

It took until 1973 for the finished result of the new model to be complete and shown at the Tokyo show. 

The rest as they say is history, as the Yamaha TZ750 took the world by storm, it was in production until 1979 before the AMA changed the F750 class rules making it no longer necessary to sell 200 units to compete. 

This opened the doors to all sorts of GP racers which easily ran rings around the now dated tech thrown at the TZ750. Furthermore, WSB was providing a place for four-stroke superbike racing, rendering the TZ750 out of place.

The legacy of the Yamaha TZ750 however is strong to this day and there remains a following for the legendary big Yam.

Table of Contents

Yamaha TZ750 Review

For 1973 Yamaha engineer Naito and designer Matsui had produced a 694cc version of the ‘73 GP bike (500 Class) it was directly aimed to compete in the F750 class and made no apologies about it. 

At the time a minimum run of 200 machines were required to meet Formula 750 regulations, which Yamaha produced and sold to privateers. 

To get around having to produce road-based machines Yamaha’s lawyers pointed out that the FIM rules did not state categorically that competing bikes needed to be based on road models and that they could be straight up racers. 

Despite the competition going berserk, the legal fight was won and the Yamaha TZ750 was the hottest new motorcycle out on the track. 

We will have a look at the bikes wins a little later, but first let’s cover the engine. 

Engine and Transmission

The very first Yamaha TZ750A was actually a 694cc machine. The capacity was achieved by bolting two pairs of water-cooled TZ350 cylinders to the magnesium crankcase of the YZR500 GP bike. 

The TZ750A and early B models had the same 64 x 54mm dimensions of the 350 twin with revised porting and a slightly lower exhaust. 

In derestricted form the four cylinder bike would have been capable of 130 horsepower. A terrifying amount of power at the time, when brakes, and tires were no where near the standards they are now.

It was for the later half of 1975 the B model received a full 747cc displacement, with larger diameter pistons providing the extra CC’s and a boost in power. 

Components for the Yamaha TZ750 engine were unique to the model and so getting things right for racing was a little tricky outside of the Yamaha factory. For example, the gearbox was notoriously tricky to work with. 

Once done right, the engine was however, pretty much bulletproof, with rings lasting a long time and piston-wear barely noticeable thanks to the backwards placement of the powerplant.

The engine was also made available for purchase directly from Yamaha for purchasers to create their own racing motorcycle. It was very popular for those involved in sidecar racing. 

Low-end torque is surprisingly abundant and the clutch is relatively smooth for a bike that is akin to a rocket launcher. 

The false sense of security doesn’t last long on a yamaha TZ750 however. As soon as you dip into the power available, you shoot off leaving nothing but a memory and a trail of dust behind at your start point. 

It is heart-stoppingly fast and the front-wheel loves nothing more than to fly through the air as opposed to riding the tarmac. 

Even by today’s standards with some truly amazing superbikes available, the TZ750 remains a jaw-droppingly quick bike that will have you holding on for your life. 

Chassis, Suspension, Handling, Brakes

The frame was all new for the TZ750, the powerplant was mounted into a high-tensile, steel pipe, double-cradle frame. 

Some would argue that the chassis wasn’t up to the job and this indeed prompted many owners to turn to aftermarket frames and other components. It just wasn’t very rigid or stable at high speed.

When you have a bike capable of high speed with immense amounts of power, stability at high speed is somewhat crucial, particularly to win races.

Yamaha knew this and while the production models for privateers largely remained untouched, those bikes produced by the factory for dedicated Yamaha racers were highly tuned machines with select materials and exquisite part selection, they were exotic machines. 

The key difference with the factory racers was increased rigidity in terms of the frame, they were upto 18kg lighter weight, they were lower and more compact, built to win races. 

Magnesium and titanium were just two of the exotic metals chosen for the factory racers; Yamaha wanted to make an impact on the racing circuit with no expense spared for the select few. 

Handling improved over the model years as did the stability of the frame and so with those two hand in hand the Yamaha TZ750 only got better.

Suspension changed from a dual-shock set up to a monoshock and overall instead of looking a little clumsy and bulky the TZ750 morphed into a powerful, sleek brute.  

The shock change went some way to making the overall ride of the TZ750 much smoother and precise. 

When it comes to stopping power the two discs up front and one on the rear are powerful enough to slow you down before the bend. They are smooth and responsive which is exactly what you need when racing a stallion of a machine. 

It may come as a surprise to riders today just how easy the TZ750 is to ride fast.

By no means is it a bike you can take lightly and it is not one for the faint-hearted. For those up to the task though and that enjoy giving it some throttle on the track with little fear then a Yamaha TZ750 could just be the tool you are looking for. 

It was the monoshock suspension, high-strength frame and wide tires that created the iconic silhouette that would be the jumping off board for all sportsbikes to follow. 

Race Wins and Awards

Let’s take a look at just some of the TZ750’s race wins.

  • At the Daytona 200-mile race in 1974 Giacomo Agostini won the TZ750’s debut race on a factory-spec bike. 
  • In 1976 Johnny Cecotta took the win at Daytona. 
  • In total Yamaha would have 9 consecutive wins in the Daytona 200 race with the TZ750. 
  • Taken road racing in 1980 Joey Dunlop rode it to victory at the Isle of Man Classic TT, setting a lap record on the Snaefell Mountain Course with an avg. speed of 115.22mph. 
  • John Boote won the Ruapuna NZ Championship round in 1974.
  • Interestingly, it was twin TZ750 engines that powered the Silver Bird motorcycle, the first streamliner motorcycle to break 300mph. 
  • In 1975 at the Indianapolis Mile, Kenny Roberts took home the victory on a TZ750 flat tracker. It was a controversial win going up against the Harley Davidson XR750 which had become a flat track staple. The TZ750 was shortly after banned from competing as a flat tracker. 

Yamaha TZ750 Variants

For 1973-4 the TZ750A was released as a 694cc machine, this was quickly upgraded in 1975 for the B model to 747cc. 

For 1977, the D model saw a new rear suspension set up as well as other minor improvements and the last E and F models to follow remained altogether the same as the D model. 

Alongside production motorcycles that were largely sold to private racers, the Yamaha factory produced factory-racer editions that went directly to specific racers that were part of their team to compete. These models were known as the OW series. 

It is the OW31 that is perhaps the most famous of them all with just five produced and sent out to Johnny Cecotto, Kenny Roberts, Giacomo Agostiini and Hideo Kanaya. 

Yamaha TZ750 Specifications

(for the 1977 iteration the TZ750D which would remain the same until the last F model)

Engine and Transmission

  • Engine – Liquid-cooled, two-stroke, inline-four
  • Induction – Reed Valve
  • Capacity – 747cc
  • Bore x Stroke – 66.4 x 54mm
  • Mikuni Carburetors
  • Transmission – Six Speed
  • Dry Clutch
  • Final Drive – Chain
  • Max Power – 110 horsepower at 10,500rpm
  • Max Torque – 74.5Nm at 7,500rpm

Chassis and Dimensions

  • Frame – Steel Tube, Twin Loop
  • Front Suspension – 36mm telescopic forks
  • Rear Suspension – Yamaha monoshock
  • Front Brakes – 2 x 300mm discs, two-piston calipers
  • Rear Brakes – Single 300mm disc, two-piston caliper
  • Dry Weight – 152kg
  • Wheelbase – 1407mm
  • Fuel Capacity – 29 litres

How Fast is a Yamaha TZ750 ?

The TZ750 domestic release of 1978 had a top speed of 186 mph.

How much is a Yamaha TZ750 worth?

Today, hunting down what may be the holy grail of two-stroke racers will prove difficult as there are not that many Yamaha TZ750 models still alive and kicking today. 

They are coveted as key pieces of motorcycle history, and to own such crucial pieces of history, the cost is high. 

This Kenny Roberts Flat Tracker replica is a pretty cool looking bike built to a very high spec and has an asking price of £9,500. 

While it is a bespoke motorcycle and obviously not an original TZ750 it is a nice tribute to a rebel rousing machine that knocked Harley Davidson off their podium at least once.

When it comes to prices of genuine original TZ750’s let me show you some of the nicest examples I came across:

Yamaha TZ750 For Sale Yamaha TZ750 For Sale

This stunning TZ750 was owned and raced in Macau in 1980. Immediately after the race Mike loaned it to the track museum where it remained until this year when the Padgetts purchased and imported it into the UK. Currently listed for £75,000 but open to offers from serious buyers/collectors.

I may earn a commission if you make a purchase, at no additional cost to you.

Car and Classic have one Yamaha TZ750 currently advertised and available now for £59,999. 

Raresportsbikes highlighted one listing from eBay, where the bike sold for $65,000. 

Looking back on older listings from the last 5 years or so, prices seem to have risen significantly, in a short period of time, likely due to the rarity of finding a TZ750 on the market in both the UK and US. 

Bonhams were advertised one for auction in 2015 for around $40,000. 

Verdict

What a motorcycle? Is there anything left to say? 

The TZ750 blew the Formula 750 racing class away when it arrived, and went on to perform over and over again to high standards until four-stroke Superbike racing essentially deemed big two-strokes obsolete. 

I think that many sportsbike designers and owners owe a big thank you to Yamaha for the innovation of the Yamaha TZ750. It was that base that we have come to know today as the standard for sportsbikes.

Yamaha TZ750 - The Holy Grail of Two Stroke Racers

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