Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/125790
ROAD ~'E5'·: YAMAHA 250 ·DS > ~ ~ r.; Z ~ u ~ By Art Friedman In the mid-sixties, 250cc displacement street machines were onc of the strongest classes going. In recen t years the 250 class off-road machines have boomed, but the 250 street machines have floundered and all but disappeared in this country. Honda, Bultaco, Ossa, Oucati, Harley-Davidson, BMW, and Kawasaki are some of the manufacturers that have stopped marketing their 250 road machines in this country _The probable cause fOT the decline of the 250 road machine is the rise of the 350 road machine which offers more punch with about the same handling and weight characteristics for only a slightly higher price. A manufacturer that offers two very similar machines in both the 250 and 350 categories for road use is Yamaha. Can a 250 justify itself when it has a bigger brother that is only sligh tly more expensive? After riding the Yamaha OS·7 we would have to answer with a qualified but enthusiastic affirmative. Yamaha has been building and updating their 250 since the early sixties. They have also been building a 250 road racing machine, the development of which has paralleled the street machine in many respects. This year they both feature near-iden tical frames, and the road-holding characteristics of the street legal machine reflect its parentage. In fact, the TO-3 road racer and the OS-7 roadster resemble each other more than the street and racing versions of the 250 Yam have since the TO-l road racer went out of production. The result is that the OS-7 is a very reassuring and enjoyable bike to ride through comers. The only difference between the 250 and 350 twins is the engine. They both have the same stroke, but the 350 has a bigger bore. This means that parts are largely interchangeable except for top end pieces. While this may not seem too important, it means that parts will be more likely to be stocked by a dealer, and it helps to keep prices down. To the owner of one of the production racers it also means that he can change classes with a top end swi tch. The tires. SUsPension and brakes of the 05-7 are excellent. The little engine will run on Bulgarian regular (72 octane) without complaint. The use of the highly leaded ethyls is likely to put the spark plugs in an early grave. When being pushed hard, the OS-7 only gets 40 miles out of a gallon, but if you back off and cruise you can find about 55 miles per gallon. It ----------------------- --------------1 I I I I Bike Back Bag I I I I I I I reg. $2.95 FREE with 1 Year Subscription while supply lasts Fill out subscription blank on page 8. Enclose it with check or money order (sorry. no billings on this order) AND this coupon. We will ship you this bag of a thousand uses by return mail ... FREE. check here 0 Enclosed is my subscription blank and $10.00 for a year's subscription to Cycle News. Please rush my. free Bike Back Bag to: ~ Name Address CitY. _ _ . 1~ State Zip smokes a surprising amount when cold, but it clears up pretty thoroughly when warm. Starting is a one kick business. If it is cold, you use the choke and take it off after a few seconds of running. All very simple. There is no electric starting, but it would be completely unnecessary. If you manage to stall it at an intersection the kick starter is attached to the primary system so you can start it in gear with the clutch in. The engine is surprisingly strong and performance is tather spectacular. It is always possible to be going too fast when you en ter a freeway. Acceleration is on a par with, or better than, some bikes of more than 500cc that we have tested recently. A lot of the credit has to go to the five-speed transmission which is very well spaced and aIJows you to use most of the engine's 30 horses all of the time. On the other hand you can run it down to two and a half grand, and it won't complain. The engine is very flexible. Yau will never need more power although there may be those who want more. Out at the Cycle News Secret Test Track we were able to coax an indicated 95 miles per hour out of it. At high RPM it feels as though it is just running out of breath. The removal of the air cleaner migh t help. Bigger carbs / certainly would. A nice thing about the running-out·of-air thing is that you needo 't worry abou t the tach /leedle inadvertently findins- its way into the ./ great red wasteland. The engine runs out of air before it over-revs. The DS-7 can be used for touring, but the engine is twisting righ t along at highway speeds. The tach reads 5,800 at 65 miles per hour and 6,400 at 70. It is very smooth at all speeds. A problem with using it as a touring bike is that the seat is a tad hard for really extended trips. Hard seats are something that one adjusts to, and there are people who have ridden around the world on earlier model Yamaha 250 twins. What the Yamaha OS-70 does best is play on the moun tain roads. The brakes, suspension, engine, transmission, and controls all lend themselves to fast riding. Yamaha has always made a big deal about their brakes. and it is more than an advertising hype. The brakes have excellen t feel and are capable of locking both wheels with 300 pounds, people on board at 80 miles per hour. That is good braking. What is strange is the fact that Yamaha is going to disc brakes next year. We never found a si tuation "Ibere the brakes would fade or do anything unfriendly~atsoever so a discJCems unneces~ ~~.is well that the b"rakes do suc'! a good job of slowing you down, because engine c6mpression doeSll't slow the machine in the least. That you can lock the wheels at high speeds isn't a reflection on the tireS either. The tires held on through....die worst that we could dish out. One staffer became involved with a tricked-out Lotus Elan (that's a car) up ... . _ J Weight Lifting? GET IT UP WITH A'FLOATER' SUPER LIGHT 211N FRONT WHEEL S'ee' RIm $5995 Alloy Rim $6995 PLUS FREIGHT For all Bultaco 5 speeds and can easily be modified to lit other brands. We have combined stainless steel spokes and double sealed bearings to give you a light weight rugged wheel. The FLOATER steel wheel weighs just 11',lbs.. alloy wheel 1Olbs. both complete with brakes. MX accessory catalog 50¢, FREE with order University Honda Bultaco Kawasaki & C Z 5908 Roosevelt Way NE Seattle Wash. 98105 •• The 0$·7 shares a 101 of the abilities of the Yamaha 250 road racer.