Where Legends Began ...
Kel Carruthers recalls the early
days of the TZ700
by evan williams
The mighty Yamaha TZ750 was
one of the legendary race machines of the 1970s, winning races for nearly
a full decade -- including the Daytona 200, which it won nine times in a
The TZ700/750s's first win was Daytona
in 1974 with Giacamo Agostini -- Ago to his pals -- at the helm. Ago came
from the pole, raced with Roberts and company for a while, and was gone.
The TZ750's last win was at Pocono
1983 with Gregg Smrz bringing the aging machine home that day. Doug Brauneck and
Miles Baldwin made it an all-Yamaha podium. The TZ was the dominant machine
in AMA racing for years, but faced stiff competiton at times from Kawasaki,
Suzuki and was replaced as the class standard in AMA F-1 racing by the
But, while the coals were hot ...
The winning was not limited to just factory riders, almost anyone with enough cold hard cash could buy the TZ750 from a Yamaha dealer. In total, Yamaha sold nearly 600 of the machines, and many more were constructed from spares.
With all that success, one might
think it was easy for Yamaha. It certainly didn't begin that way...
Although it initially displaced 700cc,
the machine was called the TZ750 because it had been designed for the Formula
750 class in Europe. The FIM had banned it before the TZ ever turned
a wheel, but the machine remained AMA-legal.
TZ pilots Kenny Roberts (2) and Skip
Aksland try to control their 140 horsepower beasts during a mid-1970s AMA
national at Laguna Seca.
image by the guy whose name dean can't remember
The spec sheet tells the tale: the
TZ700/750 was an in-line four two-stroke, with reed valve induction and
a fragile dry clutch. Simply put, Yamaha's design department grafted two
detuned 350 cc race engines together and came up with a somewhat conservative
design that put out 90 horsepower. That was more than enough to shred
every race tire of the day. The bore/stroke ratio was 64mm x 54mm.
1969 250 world champ and 2000 Chaparral
Suzuki crewchief, Kel Carruthers, recalls the introduction of the TZ700,
way back in 1973 when he tested the machine in Japan.
"When I first rode it in Japan I
was a little disappointed in it," recalls Kel.
"I was Yamaha's number one rider
at the time, and I went over there to test it. So I flew over and got ready
to ride the bike at a test track. They said, 'Kel-san, the bike is good
except for one small problem'. Well, the problem was the thing used to
just shake it's head at any speed over 160 miles per hour. Incredible
tankslappers! I mean it was scary..."
"Another rider went with me, and
after a couple of laps he came in and refused to ride it any more," recalled
Carruthers. "The Japanese said, 'Kel-san, now it's your turn. You try'.
"Being the young idiot I was, and
being Yamaha's number one rider at the time, I went out and did some more
Kel's knowledge of motorcycles that
later benefited Kenny Roberts and Eddie Lawson win World Championships also
helped tame the TZ. He says, "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 TZ remained a brutal dance partner
to the unsuspecting rider, however.
"Everything on it was just too flimsy,"
confides the 1969 world champ. "The first time we tested over here, at
Ontario, we had Kenny, Gene Romero and Donnie Castro on the bike. I can't
remember what lap times Kenny was turning, but Castro and Romero were like
eight seconds slower. Basically, they couldn't ride the bike. It scared
them because it wouldn't handle like they wanted it."
"I had just retired to run the race
team, but I got on it to do about five laps to see what the problem was.
I was about a second and a half off of Kenny's times. I just piddled around
the corners and held it wide open around the banking. They were fighting
it all the way around the track instead of letting it do its thing. The
bike was very flimsy because it had these little-bitty baby fork tubes
Carruthers thought the initial version
could have been even better. "It wasn't as fast as it could have been.
They were really conservative in the way they built it. After about three
or four races, we had another twenty horsepower.
"Then the chassis really started
to flex," laughed Kel.
And so the legend began.
the 1974 TZ700 and the 2000 R7
||3.25 x 18
||3.5 x 17
||3.5 x 18
||6 x 17
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