Cycle News - Archive Issues - 1990's

FIRST RIDE (Left) An engine cutaway shows the in si des of the R6. The little 600 , unlike Its sibling R1, uses four valves per cylinder rather than f ive. Why? Because the benefits of having five valves only come into play on engines w ith a larger bore than' the 65.5mm found on the R6. A lso, a 750cc-sized clutch is used on the R6 - some 14mm larger than the clutch found on the VZF600. (Below) The man : Kunihiko Miwa is the project leader on tlie new R6 and he was also the man behind the R1 that made its debut a year ago. (Left and above) A conventional 43mm provides damping up front while the rear gets a Bilsteln-type Soqi shock. Although we tested the unit in Australia with Bridgestone rubber, the bike will come equipped with Dunlops for the U.S. market. wlfour Displacement . Bore ,,"stroke . Compression ratio . Maximum power .... Maximum torque . . . . . @ Lubrication . Carburetion . .Keihin CVRD3] wit Primary reduction ratio (1. Secondary reduction ratio .. .45 (3.000l Clutch Wet. multiple disc Transmission . .C onstant-mesh 6 -speed Gear ratio 1st 3]/13 (2.846) Gear ratio 2nd 3]/19 (1.947l Gear ratio 3rd 28 /180.556 ) Gear ratio 4th 32/24 (1.333) Gear ratio 5th 25 /21 ( 1.190 ) Gear ratio 6th 26/24 (J .083) Final drive " Chain Generator .' : AC magneto Chassis Overall length ]9.7 in. Overall width 27.2 in. Overall height .43 .5 In. Seat height 32.3 in. Wh_lbase . . . . . . . . . . 54 .3 in. Minimum ground clearance . .5.3 in. Dry weight 372 lb. F...- type Aluminum Deltabox II ke/trail 24' /81mm pacity .4 .5 gal. . . . .Fully adjustable Kayaba 43mm conventional 00 0\ 0\ ...... 00 ...... J-< Q) .c S Q) :> o Z 14 opic forks wi 5.1 in. travel -type aluminum swingarm ac ross system wI single Iy adjustable Soqt shock and 4 .7 in. travel . !Dual 295mm discs r-piston calipers 220mm disc ·piston caliper tim es w h ile o the r p arts were w et. It mad e the going tricky at times, but further pro ved th e co nfide nce th e R6 inspires in its rider. W hile the s tree t r ide gave us a glim pse of what the R6 is capable of, the day a t Philli p Islan d showed us what Mr. Miwa and crew had in mind when they designed the bike. With a d ry weight 0(372 pou nd s, a claimed horsepower output of 120 horsepower (this is likely obtained with Hurricane Mitch-like air being forced into the bike's ram-air svstem - Yamaha claims the R6's sta tic horsepow er is 108), a wh eelbase of 54.4 inches and rake and trail of 24°/ 81mm, it was obvious tha t the bike would work well on the race track. Although Phill ip Island pro vid ed only one oppo rtu nity for a quick rightleft transition, the R6 showed what sho rt and steep can do for turning response. Not that its light wei ght didn't also factor into th e bike's flick ability. Wh ile sh ort and steep usually throws stability righ t ou t the window , none of the testers complained about the slight wag in the bars on the exits of so me of the slower comers while un der heavy acceler at ion . (No te to lawyer s: Your clie nts don 't need a steering da rnper. ) If the bik e's ab ility to change d irectio n s wi t h m in im a l ride r inp ut was impressive, so to was the bike's sta bility u nder heavy brak ing. When yo u exit the Sou th ern Loop a t Ph ill ip Island, you then negotiate a high-speed run through a fast left before yo u a rrive a t Honda Co rner, a second-ge ar ri ght-ha nder . Carrying a lot of speed through the fast left and the n havin g to slo w th e bike while downs hif ting for the slow righthan der was an easy proposition on the R6. A simple squeeze on the front-bra ke lever go t the bike slowed withou t any unpleasant movem ent from eit he r th e front or the rear end as the four-pist on calipers did their job in conju nction wit h the 295mm front di scs. There wa s also no noticeabl e brake fade, tho ugh Phillip Isl and is n ' t particul arly h ard o n th e br akes, wi th on ly two comers that really r equ ir e so me h a n d iwo r k w ith th e binder s. It is worth noting tha t part of the positive feel from the front obvious ly came from the front tire, in this case a Brid gest on e. Wh en the bik es arrive on A me r ica n so il, they' ll be fitted with Dunl op s, but there definitely won't be a drop in performance with the D207s. Th e harsh n ess that was readily apparent from the rear su spension while on the street ride never rea red its ugly head while running around the mostly smooth Phillip Island track . Wh at ever se tti ngs th e technicians came up w ith for the race tra ck were mor e than adequate, an d I never mad e any cha nges in regard to eit he r th e fu lly a d jus ta b le 43m m fro n t fork or to th e rea r Soqi shock . Ditto for rid e heigh t. The scaled down version of the R1's Delt abox II chassis is extremely rigid , but it was designed to be precisely that a n d it's right at home on the race track, feeling a heck of a lot like a TZ250. The bike's overall ground clearance is top-notch. According to Yamaha, it takes 56 degrees of lean angle to touch the feelers on the footpegs, and grounding the fairing or the pegs never en tered into the equation at Phillip Island . Even the fas ter testers in our group had to wo rk to the get the bike to touch down. So how fast is it? At th e end of the Ga rd ner straight, most test ers rep orted s peeds in th e 165-mp h ran g e - wit h Oliver sq ueaking 166 mph ou t of his. He no doubt got a better drive out of the last corner - a t least on one occasion than the rest of us mere mo rta ls. Naturall y, tho se spee ds came from the bike's speedometer and actual speed is ob vious ly lower, bu t the R6' s top-end performance will put it at the top , or nea r the top, of the class. Only a radar gun wi ll give us actua l numbers... The same goes for hors epower figures, which will hav e to w ait until we can get ou r test unit on the White Brothers dyno . And , yes, the bike does rev to 15,500 rpm, bu t power seems to peak at aro und 13,500. While the power doesn't increase bey ond 13,500, there isn' t an appreciable drop, making the overrev usefu l. The R6 that was assig ned to me dur- . in g b oth port io ns of th e r ide ne ver missed a shift - and ther e we re non e of those pes ky little false neutrals that preproduction un its often brin g with them to th e ra ce tra ck . Eac h clic k between gea rs was smoo th and p recise, and the cl u tch , th ou g h a bit grabby a t times, fared w ell throughout both da ys of testing . I came back fro m Australia raving to my cohorts abou t the R6, and some of th em raved b a ck a b ou t the Hond a CBR600F4 that they'd recently tested . The y raved, I raved ... and we've already started to argue abou t which of the 600s will prove to be best when compared against each other in a later issue. If nothing else , this yea r' s crop of 600s will provoke a lot of raving. The ma nufacturer who ....'ins the AMA 600cc Supersport class at Daytona will get to do their raving the loudest and it'll have an immedi ate impact on 1999 sa les figures. After a few yea rs of being trodden on in the 600cc Su persport wars, Yamaha has a good cha nce of being on top come the first week in March. Just how good is the R6? Put it this way: I thou ght we were going to have to get a p la sti c s urgeon to rem o ve th e smile from Rich Oliver's face every time he got off the bike at Phillip Island. Congratulations again, Mr. Miwa. l~

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