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The two bikes look alike. handle alike. and share m.oat of the same pans. even the carbs. You can 18U them lpart by the front brakes and the paint. The 250 i. brown. 350 purple. Reviewl The Yamaha RD-250 a RD.350, twiD twins Photos by Art Friedman and Too Rafferty Except for the front brakes, paint jobs, and ti~e sizes, the 1974 Yamaha RD-250 and RD-350 are outwardly identical. Because they share the same lower ends, the same frames, the same 28mm carbs (with different jetting), and the same six speed transmission, the bikes invite common treatment. They are very much alike to ride. Handling is the same, and the con troIs fall to hand the same way. The differences are in the feel of the brakes and ·the' powerband and throttle response. Top speeds are within a few miles per hour of each other. 1 All of this similarity leaves you wondering why there is a one bundred dollar difference ($ 795 and $895) in the costs of the two machines and indeed why Yamaha makes both bikes at.-;Ul. Or it does until you ride them. Then you find subtle differences. Prior to this year the bikes were much the same. They were both snappy little front wheel lifters that exploded out of comers and had gobs of horsepower at top end. Since their introduction, however, the 350 has changed. It is interesting to note that Yamaha c1ajms the same amount of horsepower '(30 @ 7,500 RPM) for the reed valve RD-250 as they did for the older piston port 250, the DS-7. But the DS-7 had more torque (28 ft.-lb. claimed @ 7,000 RPM) than the "Torque Induction" RD-250 (21.1 ft.-lb. @ 7,000 RPM). The RD-250 can get away with it because it has a six-speed transmission and can operate within a smaller powerband. Acceleration is sligh tly belter on the newer hike, but only slightly. The 350 seems to have made the change to reed valves and a six-speed with more of what the consumer might have anticipated. Clajmed horsepower went from 36 at 7,000 RPM to 39 at 7500 and the same torque (28 ft.-lb.) is claimed but at 7000 RPM instead of the old R-5's 6500. The effect of reed valves, despite the "Torque Induction" label, has been to rajse the powerbands. Both bikes are very peaky and come on the pipe with a rush. The surge of power is sufficien t to tift the front whee,1 in first or second gear on either bike if the throttle is snapped open. On the RD-350 that we tested last year, the front wheel sprang into the ajr with particular alacrity. This year the machine was changed subtly. There was a small stu tter in top end throttle response tha t took the edge off high RPM acceleration. It also made it harder to do wheelies unexpectedly. We suspect that Yamaha did it intentionally to avoid the spectacle of a new customer looping it as he drove away from the dealer. /t's hardly noticeable around town, but out in the mounta;ns or on the . racetrack the loss of top end power is brough t to your atten tion. The 1974 RD-350 isn't the same superbike-like jet that the '73 had been. /t's still faster than any other 350, it just isn't as fast as it was. The RD·250 hasn't been similarly devitalized. It runs cleanly to red line and does wheelies like it always did, which is to say not as spec.tacularly as the 350 used to, nor as unexpectedly. Keeping your weigh t forward will keep the fron t wheel on the ground no matter what you do with the throttle. It is more powerful than any other 250 sold for the street and snappier than the 350 but not as quick or as fast. The other difference he tween the two bi kes is in stopping capability. The 250's brakes aren't as good as tile 350's. The reason is that tile 250 has a double leading shoe unit on tile fron t and tile 350 sports a single disc. Both bikes will lock the front wheel when the brakes are cool. The disc will continue to, but the 250's drum fades under intense use, and tile drum seems to begin to wear out after several hundred miles and lose power. Although botll brakes are capahle of wheel-lock, the 350 will deliver more stopping power because the tire is wider. The disc comes on the European RD-250's and wouldn't be out of place on this side of the world eitller. The rear tire on the 350 is a 3.50 x 18 and seems to stick better than the 250's 3.25. In addition, the slightly improved ground clearance offered by the larger tire can be appreciated in hard cornering. The footpegs are about the first thing to touch down. Clearance is adequate but could be improved. Handling in general is light and quic k. A road with lots of hajrpins and closing radius comers is a Y amaha ~oad. A road with fast bumpy turns isn't as comfortable. At over 80 MPH tIley begin to try to wobble a little. Most of them don't seem to wobble too badly, neitller of this year's test machines did and last year's test machines didn't at all, but one staffer bought one to use for production racing and found that it wobbled despite his attempts at finding a remedy. (Road racing tires made it worse.) There is obviously some variety in chassis. We experienced no trouble with -either machine despite fajrly thorough thrashings administered to both of them. Because of smaller jet sizes, the RD-250 had better gas mileage. Both are comfortable for long periods and the seats are long enough to calTy two people. The RD-250 will cruise in the fast lane of the freeway with two persons aboard and will stop at the limit of its tires with two l60-pound riders on board. Our 250 seemed to have a more optimistic speedo. --Because they're so similar the $1 00 difference in price tags seems a little strange_ There certainly isn't enough difference in the motorcycles that the 350 costs Yamaha $100 more to build. They spend more ~ maybe - on the disc. More than likely somebody has found that they can sell enough 350's at $895 and enough 250's at $795 to make it worthwhile. The 350 offers a few more beans and better brakes. The 250 has slightly snappier power characteristics and enough beans of its own to do almost anything you ask of it. They're both the fastest things in their respective classes. You decide. • The engines are externally identical. Specifications 250,350 Price Displacement $795, $895 247cc, 347cc 54mm, 64mrn Bore Stroke . Compo Ratlo Carbs Starting Weight Wheelbase Fuel capacity Fue Iconsumption Tire, front Tire, rear , 54mrn j 7.1:1,6.8:1 (2) 28mm Mikuni Primary kick about 325 lb. 52.1 in. _32 gal. 42 MPG, 36 MPH 3.00 x 18 3.25 x 18, 3.50 x 18