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(Above) Ya m aha: "We're m aking the YZ125 ou r first priority in 19 8 6."
(Below) The least -c hanged o~ the bunch is the Honda CR.
(A bove) An all-new motor and rear suspension highlight the Suzuki.
(Bel ow ) Kawasaki 's bidding f or a th ree -ye ar 1 2 5 cc class sweep in 1986.
Showdown '86: Kawasaki KX125E1 vs,
Suzuki RM125G vs, Honda CR125R YS.
Yamaha VZ125S: Part 1
All are belter,
but one is best
By Kit Pa lmer
Another year has begun, and with it comes a
new crop of 125cc motocrossers from J apan:
th e Kawasaki KX125EI ,.theSuzuki RMI25G,
the Honda CRl25R and the Yamaha YZI25S.
All of th ese m oto rcycl es ,
exce p t the Honda , a re rad ica lly
cha nged for 1986. Last year's
125cc kin g , th e KX, has co m p letel y new . totall y redesigned rea r
suspe ns io n, major eng ine mod ifica tions a nd new styling; th e sa me's true
of the RM a nd YZ. H onda. on th e
ot he r han d . did not radi ca lly cha nge
th e alread y-p ro ven C R. Ins tead . th e
'86 C R is refi n ed a nd lo ok s idc n rira l
lO las.t yea r>, exce p t for hav in g go lda nodized runs a nd new.logos.
Technical
10
Ka w asak i K X 125E l : For th e past
«l" p le of year s. Kaw asak i has dom i-
nat ed th e 125cc clas s, especia lly in
198,1, whe n th e KX eas ilv ru led . A
year lat er, the KX was slig h t"Iy changed
a nd still dominat ed ; how ever. th e
co mpetitio n got closer - a littl e too
close fo r Ka wa sak i, so the factory
wen t all -ou t a nd developed a n a llnew race r for 1986,
All fou r o f th ese bi kes ha ve wat er cooled. two-stro ke, reed-va lve mo tors.
The Ka wasak i has smoked th e o ther
th ree bik es for the la st two years, bu t
for '86, Kawa sak i decided to co mp letely revamp the motor sta rt ing
with the Ka wasa ki Int egra ted Powervalve System (K,I.P .S.). The exhaust
valve is no w 3illlill ilrg el . a i1<1 o th er' ,
m in or cha nges increase ex ha ust gas
flo w for m ore power th roughout th e.
powerban d.
To ga in even more horsepow er ,
th e n ew cylinder has 3m m wider su bpOTtS (12mm, fro m 9m m) , larger sca ven ging POTtS; th e pi ston has one
rin g in stead o f two to reduce friction
(sam e as th e Honda ). The 56.0x
50.6m m bo re an d stro ke, l24cc actua l
d isp laceme nt and 9;35: I co m pressio n
ra tio remains th e sa me .
Water-cooling is handled by o ne
la rge radiator mounted o n th e left
side o f th e m otorcycl e in front of th e
ga s tank. The top of th e radiator n ow
ha s a fla t top for eas ier acces s to the
radi a tor ca p.
The 35m m (u p from 3'1 m m) ro u ndslide Miku ni ca rbureto r is a ll new.
Instead o f ha vin g an ova l bore, it now
ha s a keyho le-sha ped bore for better
gas flow. At srna ll throule o pe n ings,
just as th e car bureto r 's slide rises, th e
na rro wer th roa t area a t th e lo wer half
of the bore pro duces h igher inta ke
velocity int o th e cylin der to improve
th rot tle respo nse. As the slide ri ses
a nd throt tle a p p roaches wide-open ,
the bo re widen s. a llo wi ng more fuel
to reach the cylinder a t h igh rpm .
La st yea r's l\liku n i had a rig ht -side
choke lever: n ow ir 's a left-side push !
pu ll knob.
W ith th e n ew rear sus pe n s io n
system. th ere is more room for th e
a irbo x, which is now n oti ceabl y increa sed in size to im prove breath in g .
Access to th e rou nd filt er eleme n t is
sti ll from th e left side o f th e bike a fter
removing three phi ll ip s-head screws
a nd th e pla st ic, black-pa in ted co ver.
A wi ng nu t ho lds the cleme n t into
pl ace.
Ign ition timi n g ha s been slig h tly
. -reta rded to 13° BTDC @ 11000 rpm .,
I
[ronnso' BTD C@ !looarpm. .
'
T he ex ha us t pipe is now two pi eces, ins tead o f o ne. Wh ere th e fat
port io n of th e pi pe narrows down,
th ere is a O -rin g-equipped slip fit to
th e narrow en d p iece o f th e pipe. A
spring holds th e two p ieces together.
A rebuildablc , a lu m in u m muffler
mounts to th e fram e in two p la ces
in stead o f o ne.
T he six-speed , cons tant mesh transm ission is th e same . as is th e wet .
mult i-pl at e clutch .
Suspension a nd fram e a re co m pletely redesigned, T he silver-pa in ted ,
h igh-ten sile-steel fra me now has a
detacha ble a lum in um rear su bsectio n.
T he narro wer rear su bsect io n can be
detached witho u t ha vin g to remove
the a ir box or th e rear exha ust p ipe
and silence r.
The rear Uni -Trak , single-shock
suspension is o bvio usly all new. Gone
a rc the stru t an d roc ker a rm , repl aced
by a linka ge-a nd -lever design . T he
Kaya ba shock is now mou nt ed so lid ly
a t th e top a nd co n nec ts to th e lin kages a t th e bottom, undern eath th e
swingarm . T he re are a num ber o f
rea so ns whv Ka wasaki went to th is
system : it nia kes room fo r the la rger
a irbox a nd a llows use o f th e detach a ble rea r su bsect io n; overa ll mot orcycle wid th is redu ced ; and th e shock
is mounted m ore fo rw ard a nd low er
in th e bik e to cent ra lize weight a nd lO
lo wer th e bik e's o vera ll center o f
gra vity.
T he remot e-reser vo ir shock h a s
four-way extern a l rebo u nd dam ping
adj ustme nts, sepa ra te h igh - and lowspeed co m p ressio n damping setti ngs
a nd a tem perat ure com pensa ting va lve
to reduce fad ing.
The Kaya ba from fork is eq ui p p ed
with the T ra vel Control Valve (T CV),
which is designed to gi ve pr ogressive
damping actio n as the for k compresses
