AUTO WORLD BIKERS

Yamaha has been getting most attention for their new line of four-strokes introduced in 1973, including the TX-750 and the TX-500 (tested in this issue), but their standard two-stroke line has been getting much better along the way and deserves its share of the limelight. Yamaha is constantly developing and bettering their product regardless of how successful it already is. On the two-stroke side this included the recent adoption of reed valves, first in their competition dirt bikes and then in two of their street twins as well. Further development of the road valve principle possibly has in store even greater advantages.
As far as saleable new models go, everyone of course is waiting to see who is going to be the first out with a full production Wankel. Yamaha has one in the works and it should hit the dealer's floors sooner than anyone expects. Many of us, however, are maintaining a wait-and-see attitude after the water-cooled 750 Four never really made the scene. But rumor has it that water-cooled multis for Yamaha are definitely still in the works.
Yamaha's new 500cc four-cylinder road racers are keeping that speculation very healthy. Possibly we'll see a 500 street Four even before the 750.
The biggest changes for the 250 and 350 RD's came last year when Yamaha incorporated the reed valving along with six-speed transmissions.
The 1974 models retain those advancements with further refinement. One step up we'd like to see is a disc brake up front. The RD 250 is a very fast 250 and it's heavy.
With two-up the added control of a disc brake would be worth the extra price. The price factor is probably the major reason for Yamaha withholding the disc.
Some short riding seasons revealed the same fine handling we've come to expect from Yamaha with the benefit of smoother power delivery at low rpm than we remembered with last year's RD 250. Inquiries about this yielded the explanation that there have been some carburetion changes in conjunction with the reeds, although no one was too sure exactly what had been done.
The ' 74 RD 250 gets a very mellow chocolate brown paint job accented by white pinstriping on the sides of the tank and across the length of the side panels to let you know it's the latest 250 to be had.