Cycle News - Archive Issues - 1970's

The m essage that this classic mach ine p ro jects is unmistakable. Huge (6.4 gal.) fuel tank is a Godsend on I~ng t rips at .o d d ho urs . Rider's eye view of the world : One of the most complete and usa ble in st rumen t clu sters in the business, and, yes, the clock keeps perfect t ime. Our t est b ike had 6500 miles on the register, and was ju st getting nicely broken in . Th e one Ach illes ' h eel in th e ' long travel forks is th e ra dical way th ey sack down u nder heavy b raking. Whe n thi s h app ens, rake and t rail d imini sh sign ifican tly, an d the wa y the m achine heaves and wobbles o n the en t ry to do wnhill · co rners is frig hte n ing t o be hold - especially b y foll o wi ng riders . Fo rtunately fo r th e guy o n the BMW, all th is wallowing about serves mostly as a warning. never getti ng out of hand and never really d istu rb in g the rider's chosen line. Production racers put the fix on this by installing a bottoming spring in the fork slider such that the fork leg contacts it after the first one-and a-half to two inches of fork compression from rest. This allows normal travel to co pe with surface roughness . yet severely limits the bottoming tendency under braking. The braking ca pabilities of the R90S are basically those of a GP bike, softened so mew hat to prevent inadvertent loc ku p . Front h y dra ulic leve r travel is long an d progressive, allo wing p recise three .finger control from gentle to full lockup (an d incidental ly, encouraging the rider to dive deeply into corners wi th th e brakes h ar d o n so he can be sure and ex perience th e aforementione d wallow). The rear drum bra ke is just progressive eno ug h, con trolla ble enough. th at yo u ba rely notice it s ex ist e nce. you sim ply use it to bala nce agai nst th ose al mig h ty dual disc fro n t b ra kes any way you choose. It hauls d o wn from 100 1\1 I'll to ze ro, any ti me, a ny place, repeatedly. And for 1975, the front discs have pu nch ed ho les in them so they maintain their inc re d ib le feel wi tho u t squeal even when drowning wet. So far we 've de scribed a superlative superbike with a bo ulevard ride and mi nd -bogglin g speed. The frosting on th e cake m a kes it worth S3700. Like the cloc k. Ever seen a motorcycle with a clock? Not any old garden-variety clock like they put in ca rs (that are never right and usually quit running after two days). This is a quartz-erystal clock that is always running and aI ways righ t. Always. Like p lus or minus a second a month . O r the pain t. The silver/s moke finish created fo r the R9 0 S h as to go d own as a collector's item in its ow n right (especially since the 19 75s will be Day t ona Oran ge ). Each o ne is h an d done and beca use of th is. ea ch one is different - has its o w n u n iq ue ch anges of shade an d te x t ure th at binds it to its o w n e r , I t i s sto ne castles and battlements . It exudes a kin d of Hohenzollem no bil it y , a breed o f class th at just ca n ' t be m at ch ed. S till m ore. The fl oat ing dis c brake calipers sit behind the fo rk tubes. whe re th eir wei ght is cl os est to th e st eeri ng axis so they add the leas t po ssibl e to th e stee ri ng inertia . Th e b ra ke flu id rese rvo ir is u nd er th e tan k rather t han on th e hand lebar so its weigh t. to o , is isolated fro m t he m ov abl e steering. A n electric flo at level tells when the fluid is low b y flas hi ng a pan el warning light . Noth ing is wast ed . Und e r t hat ca fe seatback lu rks a n extra luggage boot . A luxury 'to uch , for effortless preloa d setting . Wish the Japa nese would co py this id ea . T he sh ocks have ha ndl es o n the adj us ti ng ca ms so the preload ca n be se t with o u t a speci al wrench. There is a t h r e e -p osition adjus ta ble, h ydra ulic st eerin g dampe r. Th e drive sha f t is ru bber -c ush ioned aga inst sh oc k lo ad s (a go o d id ea. since shock load s are su re to resu lt if an im patie n t rider tries to bea t th e cons i de ra b le e ngin e ine r t ia while sh ift ing), a nd the final drive drai n in terval is over 70 00 mil es . Sure spoils yo u for cha ins. T he 38 m m Del 'O rto carbs have accelerator pumps powerful enough to shoot a free jet o f fuel four-and-a half fee t. The effe ct is an engine tha t makes 75 horsepower at 7200 RPM yet is never cammy an d accepts great gul ps of thro t tl e at any speed. Yo u 'd have be tt er luc k tr y in g t o m ak e an elep ha n t st u mble. At the e nd of th e ca m shaft is an Ea ton "gearo tor " type oi l pump th at deli vers 3 70 gallons p er m inu te at 6000 RPM . • Th e electrical sys te m has a 28 0 Watt genera ti ng ca pacity (solid sta te rectifier co nt ro l}, an d th e starter gru n ts o u t just o ve r a ha l f a n h on e s t (D IN) hor esep ower, It ne eds to. s ince the 9.5; I co m p res sion, 900cc flat twin is a heft y pump to turn ove r. So meti mes it 's he fty enough to stall the starter and require a second stab at the bu tt o n La get things spinning. The qua rtz-iodine headlarnp is the brigh test thing that's legal (a nd has a special dispensation fro m th e Feds at that). Penetration is adeq ua te for 70 ·plus cruisi ng, th ough the pa tte rn could use m ore sp read close-in for "seeing around co mers" at night. Nothing in the electrics failed during our test. There are two glove boxes under the hinged. lockable seat. One is fo rward . where th e su per-fine toolkit nestl es along with the BMW shop towel an d the o wner's manual. To the rear, under the "cafe " seatback, is a "trunk" b ig enough to accept some rolled u p cloth es and a spot of lunch. Now fo r the picky-picky. Noth ing is perfect . not even a S3700 m o to rc ycle (sob l}. The seat is firm and co mforta ble but slip pery. Riders love it. because it makes hanging off easier. Pass en gers are less enthusiastic, because the slic k seat ma kes it nearly impossible to get a good grip against the beast's savage go an d stop power . The spee do me te r reads about 10% optimistic at 100 MPH . (Picky, picky , pi cky .) Our test b ike was a so me ti mes rel uctant co ld starter. and a very rel ucta nt col d idler. Th e sides ta nd must be titanium, because it strikes up a sho wer of sparks wh en it d rags th e paveme nt. Uh , ab o u t th at sid estand. It is sp ri ng load ed to pop up automa ti cally wh en th e motorc ycle is moved. If th e bike ge ts nu d ged inadve rt ently, ov er she goe s. We think th e R90S (an d it's not alo ne th is year ) sits too close to vert ical on the sides ta nd, Since m ost ro ads are ca m be re d for drainage, whe n you par k at the curbside, this puts the bike dangero us ly close to ove rbalance . The windblas t from ' a passing truck blew ours over once. The stand is configured as it is to prevent an owner from riding away with it down and hi ghsiding hi mself, which is an admirable safety idea. Still. there ought to be a better way. Fo r t he present, the best solution is self discipline. Park it on the cen t ersta nd if you don't want it to faIl over. The fork lock requires a special key with a h inged fob. so the fork tu be won't brea k th e key head off should the forks swing aro und while fishing for th e lock h ol e. We fou nd out about tha t the hard way. There's a little co mbustion r o ughn ess co m b ined with a bit of a rocki ng vibration a t low Jugging speeds. The engine is at its smoothest fro m 3 I 00 RPM on up. What else? Um mm-uh hh ... you know, yo u reall y have to work hard to criticize this m ot orcy cle , Most p eopl e will ne ver use u p th e available cornering clearance, even th ough it Can be use d up. The racers fit a I9-inch rear wh eel and tir e to gain a little extra lift. The Bl\IW R90S co mes the closest to being a " G rand T u ris mo" mo torcycle of anything we've tested . But consider its bi rthplac e, in central Europe wh e re cabby roads are the rule, ra th er th a n th e exception and everybody rides fast. It was d e s ig n e d for a d e m an di ng environment even before it ac h ieved a ma rket nich e in this country. It speaks softly, but with great authority. It has two messages for the beholder. 1) I am fast. and 2) The m an on my back is rich . (Next year, when it's Daytona Orange, it will tend to scream the former and whisper the latter.) If you've got the money to buy it and a place to ride it that '5 not wall-to-wall traffic co ps. it's wo rth every cent of \.he asking p ric e. In an era o f big govern ment and little people, the BMW R9 0S may be th e last of the great classics. • U") ~ 'lJ ..0 E 'lJ > o Z - - Specifications Suggested Retail (West Coast) $3 69 5 Wheelbase 85 .8 in. (218cm) Seat height . ....• . _ 32 .3 i n. (82cm ) Curb weight . . . . . . . ... • . . • . . .. . . 4 74Ib . Displacement : .. 898cc Bore x strok e . ...•.. . . .. ... 90 . 70.6 mm Compressio n ratio 9 .5 :1 Horsepo wer @ RPM . .. . . . • 75 @ 720 0 RPM Ma. . torq ue @ RPM .. .55 It ·lb . @ 550 0 RPM ~ Two 38mm Carburetion Del :Orto T ype PH M Ti res .. . •.•. . .. ... • . . .. . Front 325 H 19 Rear 4 .00 H 18 Electrical 12 V 280 W out put alt ernator Fuel capaeity .. . . .. . . .... . . . . •.. 6 .4 gao Fuel consu m pti on _...•. .46/38 M PG (8est/Worst) 25

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