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/128643
2001 Yamaha YZ2 50 F Yamaha g~es ~utside the b~x ",ith its lie", quarter-liter thumper. d isda in th an b ig -b o re thumpers h ad once b een . Is the hype warranted ? Tha t 's what w e set o ut to asce r tai n as so on a s Yama ha han d ed o ve r a test b ike. We ' ve on ly ha d o u r 2 5 0 F fo r o ne m onth, but we' ve rid d en th e b ej eezu s out of it in t hat p er iod , r in g ing it out at L o s A nge le s Co u n ty Ra c e wa y , G l en , He l en Ra c e w a y , C o mp et i tio n Park , Lake E lsin or e MX Park an d Per r is Raceway . It on ly tak es a fe w lap s to real ize ho w t he YZ2 50F lik es you to rid e it nam ely , lik e you stole it - and once ou r test ers overca me th eir reluctance to ring o ut a thum p er a s if it we re a 125cc t wo -s t rok e , it w as the most req ue st ed ma c h in e in o ur te st fleet. B l es se d with t ita n iu m v al v es , light valve sp ri ngs and a sho rty piston , th e YZ F i s snapp y a n d q uick-revvi n g, even compared to its b ig b roth er , an d " pi n n ed" is ex a ctly w he re it likes to b e . Th is is n o XR 250R lug - maste r , but a bik e t h at will rac e at t he p role vel ag a in st f a c t o r y 1 2 5 c c t w o st rokes . T ha t's no t to say t h at t h is mot or f e e l s exa ctl y like a 12 5 . F o r o n e thing , the m otor pu ll s you o ut o f corners harder th an do r ing -d ing tiddlers Seven m onths ago, no o n e w o u l d ha ve con si d e red a 250cc four-st r oke a seriou s motorcycle . Yama ha h o p e s the VZ250F w ill cha nge that preconcept ion. h igh p er centage o f th ese b ik es em it- B y CH RIS J O N NUM ting th at unm ista k abl e b as s -drum PH OT OS BY K IT P A LME R A N D J ON NU M thud o f a four -stroke? Yes , it 's tru e. a - h e scene is An y Track, USA, circa 1996 ( a lso known as 1 ./ Follow m e o ve r here to th e sta rt li ne , and you ' ll see tha t the m o st p re val ent B .F. , for B ef o r e YZF) . Pr ecisel y 99 percen t o f t he bi k es in the pits ar e b ik e at t he tra c k is ac t ually a four stro k e - a serio us -l ook i ng m a c h in e two-strokes , an d any poo r so u l wh o call ed th e Yamaha YZ426F. bucks the trend b y showing up w ith an MX - converted f our-stro k e i s th e To us m otorcy cl in g d ie -hards , the su cces s of th e b ig Yamm ie thu mper subject o f i n c r edu l ou s c u ri o si t y at best, out ri ght rid icu le at worst. Judg - o ver the past few y ears now seems a natural e vo lution . But to an y o bjec - i n g fr om the a t mo s p he r e h ere , it · t iv e ou ts id e ob server, a m ore dramat - appears that th e American motocross ic m ass c h ang e in pub li c perc eption p ublic lar g ely (and c o r rec tl y) views the average thumper as a non-com - cou ld hardl y be imagined . p et itiv e, geeky pla y bike th at should keep its amp le gi rth an d d istin ctiv e so und in t he off-road real m - w ell out u nl ea sh i n g a huge m ar k e t i n g c am p a i g n t o h e r a l d i ts n e w YZ 250F . o f eye - a n d ea rs ho t o f th e h e a d y Sin c e wo rd of the bike fi rst leak ed out Now, Yamah a is goi ng for it again , www. cyclenews.com ha lf a y ear environs of A ny T rack, US A . on C ut to t he sa me v enu e ju st four yea rs l at er (3 A.F .), where we fi n d ago , a hug e amount o f ( m o st ly posi - t he pits t e e m i n g w ith bl ue -c la d generated - so m uch th at it's easy to ma c h in es - far more th an were here on our last visit. And ha rk - d o m y forget t h at , pri or t o t h a t announce m en t , quarter -liter four -strokes w ere ea rs deceive m e, or are a surpris in gl y t re ated by the MX set with ev en more 6 D EC EMBER 13,2000' cue tive) gossip and speculation has been I e n e vv s Tech Ticker ENGINE • Approxima tely .45 pounds lighter than two-stroke 250cc engine • TItanium valves (3 intake, 2 exhaust) allow light springs (achieves quick er response and better revving) • Claimed to be capable of 13,500 rpm • New Keihin FCR37 carburetor w ] throttle-position sensor & hot-start button • Low-friction crankshaft • Single shaft balancer • Lightweight magnesium cylinder-head cover • New-type liquid-cooled cylind er head wI direct intake port • Liquid-coo led, ceramic-composite-plated cylin der • Forged camshaft for light weight and high strength • Forged piston wI thin wall & short skirt for quick revving, light inertia mass, less reciprocati ng motion • Floating crankshaft for light inertia mass • Lightweight connecting rod • Wet clutch with 9 friction plates, 8 steel plates • New-design transmission wI involute spline • Thin shift cam with lightening holes in hatching area SUSPENSION • New-design shock wi needle bearing, alumin um guide & large-capacity bumper (same as other YZs) • Lightweight, extruded-alumi num swingann (same as other YZs) CHASSIS • Lightweight, high-tension steel frame wI in-frame oil tank • Alumin um subframe is 10mm lower than last year's other YZ's • 250mm floating front-b rake disc • New-desiqn front brake master cylinder & lever wI simplified adjuster & optimal lever- ratio setting (same as other YZS) • New-design clutch lever wi less-exaggerated bend (same as other YZS) • Same clai med overall dry weight as YZ250 two-stroke