1971 Yamaha RT-1B - 5-Page Vintage Motorcycle Road Test Artcle

Description

1971 Yamaha RT-1B - 5-Page Vintage Motorcycle Road Test Artcle
Original, Vintage Magazine Article
Page Size: Approx. 8" x 11"  (21 cm x 28 cm)
Condition: Good
YAMAHA RT-1B
Following in the tracks of the
world’s most successful
dual-purpose 250, Yamaha’s
360 RT-1 is sure to be a winner.
WHEN YAMAHA INTRODUCED their 250 DT-I two
years ago. it created little less than a sensation among
the motorcycling public. Owners were overjoyed with
its light weight, good pulling power and excellent handling.
Dealers appreciated the fact that it required little service. With
the success of the DT-1, the 125 AT-I and 175 CT-1 machines
evolved.
The logical successor was a big bore Single-the RT-IB a
360 with a seemingly endless list of features. At last, a
machine which is more than capable of keeping up with traffic
on the freeway is just as at home in the boonies.
Outwardly, the RT-IB and the DT-I look much alike. Their
purposeful styling is accented by a cross-brace between the
handlebars, a comfortable dual seat. Dunlop Trials Universal
tires, and quickly detachable lighting. A bash plate protects
the underside of the engine from rocks and logs. The slim gas
tank permits the rider to keep his legs in close, improving his
ability to balance. For the rider who needs more power than
the 250 DT-1 offers, the RT-1 B is the answer. It offers power
in spades!
Decidedly oversquare (80-mm bore, 70-mm stroke), the
RT-1 B’s engine pulls like the proverbial Clydesdale. Aided by
Yamaha’s five-port configuration in the cylinder, exhaust gas
scavenging is much more efficient than the conventional
three-port arrangement. Two additional ports, placed to the
rear of the usual transfer ports, steer the incoming fuel/air
charge into the area of the cylinder which contains burned
exhaust gases from the previous power stroke. As the new
charge reaches the combustion chamber area, the spent gases
are forced out of the cylinder through the exhaust port.
AN EXCELLENT TRAIL MACHINE
The RT-1 B’s effective power band begins at just over 2500
rpm and continues right up to the 6500 rpm red line. Even
with rather tall overall gearing for the street, it is an excellent
trail machine, and has enough power to finish well in 360-class
motocross races with muffler intact...
13419-AL-7102-08