Yamaha TZ-750 Retrospect Motorcycle Shopper

1 Май 2015 | Author: | Комментарии к записи Yamaha TZ-750 Retrospect Motorcycle Shopper отключены
Yamaha TZ 250

Yamaha TZ-750 Retrospect

by Jim

Road Racing Technical

Daytona is here again. in my office during lunch the day, I was thinking about my for this year’s AMA/CCS while idly looking at a on the wall, celebrating Crosby’s 200 win. Then it struck me! been 10 years since a Yamaha last won Daytona.

How have changed!

Introduced at in 1974, the TZ-750 overnight the weapon to have, if you were about winning an AMA National let alone Daytona. No other offered anything near it, in of speed, reliability and availability to the rider.

From 1974 to a TZ-750, either factory or backed, won every Daytona Add to this the number of World and National championships worldwide, and the will surely go down as one of the racers of all time.

A win at Daytona was the for the creation of the bike. By winning with a 750—as opposed to a 350 as in ’72 and Saarinen in ’73 had hoped to make inroads the big-bike market.

Unlike and Kawasaki—and for that matter had no bike eligible to compete in AMA AMA rules required 200 units of a to be produced before it was allowed to Yamaha did have the awful 750 four-…, street bike.

it into a racer was out of the question!

For years, Yamaha had been 250 and 350 production GP bikes based on works technology, from efforts in the World Championship. In 1973, engineer Naito and Matusi were given the light to produce a 750, racer. Since, unlike and Suzuki, they had no acceptable bike upon which to their racer, a radical was made; take their and closely-guarded knowledge for building GP bikes, and make it available to racers, in quantities required by the

When the news of what had done got out, other were in apocalyptic shock! The bike was essentially a bored-out and OW20 YZR 500 GP bike with valves. The bikes were to dealers by December 1973, than ninety days it’s inception.

When I my ’74 TZ-750A from its owner, Bill Labrie of St. Florida, I received the original MSO Bill was given by Barney’s when he purchased the machine. on the MSO was the purchase price: $3,600!

A dream come true.

My was one of the first delivered, and one of only allocated to Florida. The other two to John Long and Pat Hennen. As it out, it was the only one of the three ran really well.

Bill’s son rode it to a 19th at the 1974 200; 1st at Pocono and in the top-ten the of the season, earning Billy his license.

The first 266 TZ-750As were 700s. The first full 750 with bike #409-00367. kits were made so those with a 700cc turn it into a 750cc.

For an additional 111 bikes were In 1976, forty were The ’75 and ’76 models designated TZ-750B and C. These were virtually identical to the A except for improvements in clutch-plate and gussets welded to the outside of the to prevent them from

Agostini won Daytona in 1974 on the first try. For 1975, and his tuner Carruthers appeared at with a factory OW29 The bike was essentially a modified B

For the first time, the bike a monoshock rear suspension. The was similar to the motocross shock in it also had a bell reservoir at its end. This suspension travel from 3.1 inches to

This type of suspension fed its loads directly to the steering not the rear frame members. single change improved the handling and stopped the wobble the A, B and C models were known on the banks at Daytona.

Another was the new routing of the expansion chambers. The two and one right-hand pipe, still under the bike, but the left-hand went up over the transmission the carbs, across the frame, below the seat on the right This arrangement allowed for ground clearance and better shape, resulting in more and greater reliability with to the pipe.

The flat pipes of the A, B and C models good for no more than 100-mile races, before were patched and broken use. Also mag wheels substituted in place of the stock wheels. Aside from changes Roberts OW29 was to the privateer twin-shock bikes.

In it used the same frame only brackets added as for the modifications.

In Ted MaCauley’s book The Legend, photos clearly the frame mounts and seat required for the standard shocks in place. Also note the photo on page 187 of the book is as showing Roberts and his 1976 bike at Daytona. The bike is in the 1975 YZR just described.

As we see, the OW31 was a very machine in terms of its frame and gear. It is obvious however this bike was the direct of the OW31.

At Daytona, Yamaha up with four new 750s. from the engines, which visually the same as those in the bikes, these new bikes 40-lbs. lighter, and overall, and wider. Those privateers who had their twin-shock bikes the lines of Roberts 1975 and figured they would be with the factory, had a collective …. In practice the bikes 10 to 25 mph faster than anything

Because of the lighter weight and stand, they were easier to handle around as long as the wick was turned up upon exit.

The bikes exotic, to say the least. Titanium was for all fasteners, axles, fairing chain adjusters, brake pistons and anywhere else you think of, all this in an effort to weight. The lower triple-tree and engine castings were of magnesium.

Yamaha TZ 250

The steering-stem and brake were made from not steel and cast iron as on the bike. The monoshock unit was from 26mm-diameter tubing, not the tubing used on the TZ-750A, B and C.

the engines were carefully according to specs set down by Carruthers. These four plus a fifth, were intended to compete in the 1976 of the Formula 750 World Championship. Yamaha’s withdrawal from GP in 1976, the bikes had nowhere, but to compete on an international level. The factory entered one of the bikes for Kanaya to contest Daytona.

The of the bikes were loaned or to the following teams: Yamaha with Roberts; Yamaha Canada with Baker; with Cecotto and the fifth for use if he desired.

Cecotto won the race a ferocious battle with and in the process, literally left in the dust. The other factories devastated and the privateers were for copies.

For 1971, Yamaha was with the factory OW310s. For and Kawasaki that was bad enough, but to top it Yamaha had built an additional 70 to be sold to the top privateers. The OW310 —designated OW31—were very copies of the factory racer. differed from the factory in that they used no and less magnesium components.

They also differed in the standard production engine motive power, rolling on wheels, not Morris mags.

At a of $10,000, the bike was still the for privateers, the A-model had been a few earlier. With a few thousand dollars and the wrenching of a skilled the bike could be transformed a top contender. The 1977 OW31 was as the TZ-750D, E and F.

1978 marked the end of of the TZ-750, due mainly to the end of the 750 class in Championship GP racing, effective at the end of the Production ceased with the although additional bikes assembled from spares in and sold as F-models.

Between and 1979, 162 OW31 replicas built starting with No. 409-200101 and ending with No. The last bike Yamaha USA had on to sell, was sold on January 20, and delivered to an individual in Europe. the figures I received from Clark, head of the Yamaha Department at Yamaha International, it 527 TZ-750s were built by the

This of course does not into account unnumbered and engine cases which may been sold across the counter.

I consider myself lucky to owned a TZ-750, and foolish to sold it. Fortunately Scott of Bonneville motorcycle-record fame the bike, so it’s in good I was also lucky to have or should I say, have the bike at Daytona several WFO on the banks at Daytona on a TZ-750.


Surely, today super handle better, stop and are just plain-better race However, I have yet to witness a 200 that compares to the experience of a master such as Roberts, or Baker, rocket around the approaching 190 mph. If you missed the reign of the TZ-750 at Daytona, you something very special in the of motorcycle racing.

Something not to come our way again.

Jim Reed as Motorcycle Shopper’s Road Technical Editor. He’s several articles for the magazine as as other publications.

Yamaha TZ 250
Yamaha TZ 250
Yamaha TZ 250
Yamaha TZ 250
Yamaha TZ 250


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