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/128639
most of our tester riders d idn 't have a hard time starting the 426. Those who weren't rea l familiar with the b ik e someti mes struggled a little bit getting it to fire with a hot motor. O v e r all . t h er e isn 't a whole lot to say a bo u t th e '0 1 426 t hat ha s n ' t (Le ft) T he YZ ' s f o rks have been s lightly modified to i m p rov e bottoming feel. (A b o ve) The Yam a ha's quicker-revving motor makes it more appealing on tight tracks. (Right) New carburetor and accelerator-pump settings Im p rove powe r off t h e bottom. alrea dy been said abou t th e '0 0 , or th e '99 4 2 6 , fo r th at m a tt er. Ima g in e those b ikes w ith b etter th rottle r esponse an d you h a v e g o o d id ea j u st wh at it's lik e t o rid e th e '0 1 YZ4 2 6 F . CN (A bo v e le ftl As far as handling, nothing has changed (w h i c h i s a good thing). (Above rig ht ) Acces s t o the o il filt e r Is now easier thanks to the redesigned exhaust pipe. 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EN GINE TYPE: Liqu id- cooled, four-stroke, DOH C DISPLA CEMEN T : .426 cc 9 5.0m m X 60 .1 mrn BO RE f, STROKE: COMPRESSION RATIO: 12.5: I LUBRICAT IO N SYST EM: Dry sump CAR BURETO R: .. .. . . . . . .• . . . .•. . . . . . . . . . .. . .. . .. . . ... .Keihin FCR MX39 STAR TIN G SYSTEM: Kick ELECTRICAL SYSTEM : CDI m agn eto TRANSMISSION: Fiv e-speed. co nstan t m esh GEAR RATIO 1st • .. .. ... . . . . . . .. . . . . . . . . ...... . .. ... . . . . . . . . .. . ... .•24/1 3 ( 1.84 6) 2nd ... ... . . .... . .. .... ... . .. . . .. . . ... .. . . . . . . • . . . . .. . . .23/1 5 ( 1.533) 3rd .. .. .. . . . • . . . . .. . . . . . . . . .. . .. . .. . .. .. . . .. ... . . . . . . . .23 /18 ( 1.278) 4th . . .. . .• • . . • . .• . .. . . . . . . . . . • . .• ..... ..... .... ........24 / 22 ( 1.09 1) 5th .. ... . .. .•. .. . .. .. . . .... . .. . . . . . ... . . . ... ... .... ... .20/2 1 (0. 952) .49 /1 4 (3.500), D.1.0 chain 11520 FINAL DRIVE: CLUT CH TYPE: Wet , mu lti ple-disc FRAME TYPE: • . .. • . • . . • . . .. . . . . . . . .. . . .. . .. . .. . ... . ..Sem i double cradle CASTER A NGLE : 27.8·d egrees TRAIL: .4 .84 in. SUSPENION Front: Kayaba, inverted 48mm Rear: . . .. . .. . . .. . .. . ... . . . . .. . .. . . . . . • . • • .Kayaba, single- shoc k, li nk-type WHEEL TRAVEL Fron t: 11.8 in. Rear: 12.4 in. BRAK ES Front: Disc 250mm X 3.0mm Rear : Disc 24 0m m X 4.0rn m TIRES Fro nt: . . . • . . . . . • . . . . .. • .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80 /100-2 1 5 1M Rear: 110/90- 19 62M O/ A LENG TH : . ........ . .... .. • ...... .................. ..... .. .85 .5 in. 32 .6 in. O/A WIDTH : O/ A HEIGHT : .5 1.3 in. 39 .3 in. SEAT HEIGHT: WHEELBASE: .5 8.7 in. 14 .7 in. GROUND CLEARANCE: CLAIMED WEIGHT (WET): . .. . . . . .. . ... . . . . . ... . . . . . . . .. •.. . .. .. .249 Ibs. MSRP: $59 99 Most fac to ry riders take it rel atively easy up on reti rin g, but form er Team Yam aha rid er Doug Dubach is work ing harde r than ever. Most of the limelight he gets these days co mes from his continued success ful racing forays as a m em ber of the White Br others Yama ha team . but more of h is ti me is spent as a teste r for Yam aha. Your old racing nickname wa s Dr . 0 , but you 'v e pretty mu ch come t o be regarded as Dr. VZF. What's your official title? I guess I don't really have an official title. They don 't give m e a busi ness card or anything . I'm kind of an ou tside contractor for Yamaha, like a racer would be. I guess I would be considered the prem ier test ride r. I've been there the longest, and they regard me as a concrete fixture to the progra m . I test everything - even the 80 , as litt le as we do with that bike. We do have a lot of 80 kids that help us test. but I'll ride to back it up and to make sure they're going down the right path . espec ially with the engine. I do a little bit of testing with the WR, and even a little with the A TV. but not that much with those. I helped early on with the WRs. but tended to set them up like a motocross bike. saying the suspension was too soft. You have to sort of leam the ma rket and who the customer is who 's bu ying thaL Ho w ma ny hours to you think you ha ve pu t on Yam aha four-strokes? Well . it's funn y beca use. in our st aff. they all laugh and say they wou ld all lay money that I have had the mo st seat time of anyone in the world on ou r four- stroke project. since I'm involved in both the testi ng and the durability-test ing asp ect of it . I co uldn 't put a num ber of laps or hours on it, but I've got a lot 01 ti m e on those bikes. No w that you've also got the 250F to spen d time on , do you prefer to ride one m ore t han the ot her? We don't reall y have a choice of what we want to spend time on, but I can 't say enough abou t that 250 four- stroke. I joke around with peo ple and say tha t if th ey would let me go into the first corn er with th e lead , I would love to race it against the open bikes around the track. The big bikes are faster down the start straight, but I th ink that thing could hold its ow n everywhere else. Each year they let me have three bikes, and this year I asked that two of them be 250Fs. That should tell you how m uch I like the bike . Do you like riding two -strokes anymore? Every once in a while whe n I get on a two-stroke, I feel like , Oh, this is different aga in, and I like it because it 's something fresh . Usually, though, by the end of the day I wish I was back on m y four-stroke. They tend to smoothe n the bumps ou t qu ite a bit, and they' re easier to ride beca use you don't have to be as pr ecise. Maybe th at' s m y age showing up a litt le bit. Wit h the bul k of t he attention go ing t owa rd t he new 2 5 0F, why should people get excited about the 426F? Well, you 've ridden the 426, and you can see th at it's more exciting th an the previous one - more responsive, and it m ak es m ore power. It's still j ust another step in that direction . We try not to for get any of our products. People sometimes ask if we give less attention to the two-strokes now that we have the four-strokes, but we do n't. I mark on m y calenda r every day I test . I used to test 30 to 45 days a year, and now it's more like 130 to 145 da ys a yea r. Th e 250 two -stro ke [wh ich just won the Cycle News 250cc MX shoo tou tj is a perfect exam ple. How big a deal are th e titanium valve s? What happens is a val ve is thrown in one direction by the cam, and then returned by the sprin g. The heavier th e valve, the heav ier spring yo u need to hav e to pull it back , and that puts m or e load and drag on the cam. With the li ghter valves, we can run a lighter spring and accom pli sh the sam e thi ng , but you' ve just taken a bunch of th e drag out of th e engi ne. Fri cti on inside of a motor is power-robbi ng. The difference is k ind of like the differen ce of not run ning an O -ring chain. Th e other th ing that's reall y exc iti ng to m e is we c ha ng ed the c am lod e t h at ac tuates t he fu el pump, so the squirt of fuel into the engine is more pr ec is e. With th e p rev ious bik es, th e respon se was always good co m pared to othe r four -strokes, but this just ma k es it better. It's m ore crisp and m ore respons ive off the bo tt om . With those tw o cha nges, it's almost like th e jump we made in going from th e 400 to the 426. How concerned is Yamaha with Honda 's "secret " four-stroke? Well , naturally wit h any new pr odu ct, th ere's always an ele ment of m y stery . Ev ery on e work s har d to make the best pr od uct and , c urr entl y, we'r e very ha ppy wi th our pro duct. We'r e conce rne d , but co m p etition is good for the wh ol e ma rk et. Everything that an y co m pany does like tha t b ri ngs m o re p eo pl e into t his m arket. It' s exciting, but yo u'v e alw ays got to be on your to es because at any time someone could come along and surprise yo u. I don't want to cast any shad ows in thei r direction, bu t the fact that it wasn't released wh en it was sup po sed to be is a goo d indicato r for us. Chris Jonnum eye. e n e vv s N OVEM BER 1 5, 2000 11