Cycle News - Archive Issues - 1980's

co n ven tio nal gas ket. T he cra n ksha ft is a ll n ew and uses a 7mm lo nger co n nec tin g rod to improve torq ue. The solid cran k webs (sim ila r to those used on th e 250) ar e now dri lled to red uce weight and then plugged to in crease prima ry co mpressio n. Wa ter cooling is improved by resha p ing a nd en largi ng the wat er passage ways around the sub-ports and th e cylin der base. T he YZ's six-speed transm ission wen t un changed , but the wet, mu ltidis c clutch is no lo nger ac tiva ted by a pushrod through th e gea r sha ft to dis engage th e clutch ; now th ere's a cam in th e o u ter cl ut ch case th at pushes against th e pressu re pl at e to engage th e clutch . T h is is designed to g ive less pull on th e clutch lever. T he primary kickstaning mech anism is th e sa me , but th e a lu m in u m kicks tarter lever is 35mm shoner. Cha ssis an d suspension are a lso new Cor '86 . Th e single down tu be, sp lit double-crad le, red- pai n ted steel frame has a 10mm lo nger steer ing head to increase str ength a nd red uce Cork flex, and increas ed g usse u ing aro un d th e swingarrn p ivot a rea . T he Monoc ro ss, single-shock rea r sus pe nsio n system is now handl ed by an Ohl in s-buih, piggyba ck reservoir shoc k th at retains th e Brak e Actuated Suspens io n System (B.A.S.S.). It has 211 co m p ress io n a nd 25 rebound externa l dam pin g adj us tme n t sett ings. Th e lower en d of th e shock no longer con n ects to linkages above the swin ga rm : ins tead, the shock no w runs th rough th e swi ngarrn an d co n nects to th e linkages underneath . Th e new system low ers th e bik e's overa ll cen ter of gr avit y, mak es room C a la rger airbox, a nd ma kes more or roo m C a new exhaust system. or T he co mplete linkage system provid es a flatter progr ession curve and is m o unted to a str onger , box-secti on a lu m in u m swingarm. The air-adjustabl e. 43mm Ka yaba Corks have co mp ressio n a nd da m ping rates increased by 10%; sp ri ngs a re also stronger. The Yamaha ma inta ins 16 exu-mal co m p ressio n damping sett ings. T he Cork sliders ar e coa led with Alu mir e to redu ce frictio n between th e sliders a nd stanchion tubes, whi ch in tu rn , reduces th e number o f m etal pa ni cles en terin g th e C o il a nd d isturbing dampork in g actio n. Du st sea ls rep lace last year's C boo ts, ork The YZ still has a front d isc brak e. a drum rear brake and Z-spokes, wh ich now lace arou nd n ew , go ld-anodized a lu m in u m ri ms . Bridgestone M22 (fro n t) and M23 (rear) tires co me stock. Th e new gas tank, wh ich holds 2.0 gall ons, is now low ered o n th e left side to hel p lo wer th e bike's center of g ravi ty. Side panel s a re resh ap ed , as a re th e radiat or shro uds, whi ch now m ount solidly to th e gas tank a n d radiators to g ive th e radi at ors more su p p o rt. T he whole pa ckage weighs 217 pou nds wet, with a Cu ll lank , o n a cert ified sca le. Suzuki R M 125G: The RMI 25 ha s a lways been in th e hunt as best 125cc motocrosser, Last year 's RM batt led Co r r u n ne r - up posi tion with the Honda but lack of horsepower (especia ll y o ff the bottom ) really hu n th e Suzuki. T h is yea r, Suzu ki jumps into th e p ow er-valve wa rs, h opin g to regai n "horsepo wer-kin g honor s it once had. Suzu ki's pow er- va lve system is ca lled th e EVAC (also known as th e a u to.ma tic ex ha us t co ntrol), a nd it 's very sim ilar to H onda 's ATAC design . A The ' 8 6 Kawasa ki gets a refined K,I.P.S ., different porting specs, a new carburetor. an d the piston has one ring instead of two. su b-cha m ber is loca ted in front of th e cylinder h ead , and a mechan icall yo pera ted rotary valve ope ns to a llow some o f th e expelled gases to ente r the su b-cha mber at low- 10 middle-rp m ra nges , effecti vely cha ngi ng th e vol urn e o f th e exha us t system and providi~g a smoother flow of ex ha ust g-as. At hi gh rpm , th e valve closes. There's an external , spring-loaded, J" 13

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