YZ 3608
Yamaha 1975: Production Monoshocker
"Last year's works bike. " was th e phrase
used b y the gu ys a t Yamah a to de scribe
th e soon-to- be pro duction model yo u
see here .
The YZ 2508 gets a closer ratio gearbox t han the 19 74
model, plus the mono shoc k set up. The new suspensio n
adds weight , but is the hot set up fo r go ing very fast .
If you're not going very fast. it's not SO swell.
They call the YZ 3608 the "Monster Motocrosser" with a
claimed 26 .7 foot pound s of torq ue and a close ratio
five speed.
The
mos t
imp ort a nt
and
a t te ntion-dema nding design change ove r
previous
YZs.
of co urse . is th e
. mon osho c k suspension. Yamah a sta les
th at rear wh eel tra vel has b een inc reased
from th e co n ven tional 3.9 to a use f ul
6. 3 in ch es. The m ono shock itself
a p pears to be a mast erp iec e in
engineering, especially in that it 's
com pl etely rebuilda ble. We were sh own
an exploded view in the upcoming parts
book. so tha t each and every piece can
be o rdered separately fro m the de aler.
Three spring weights wi ll be a v; ilab le ,
a
wi t h th e m ed ium strengt h bei ng
ins talled a t the fac tory. The only ca tc h
in rebuilding yo ur own comes upo n
reassemb ly. You'iI have t o tu ke a run
down to th e d eal er's for a 32 0 ps i
rec harge o f nitroge n for th e d am pe ning
un it ,
Xlo st of the o ther changes w ere made
si mply to accommodate the ne w
susp en s io n.
The MX 250 gets a radial fin head . but t he fins
aren't like the o nes yo u're used to seei ng on European
bikes. They're short and stubby a nd all slicky smooth .
but as long as they coo l that' s OK.
The plain M X brother to the very costly big bo re YZ is
a radial head equipped 400. A 400 Enduro model is
also offered .
The f rame, o hvio us ly. is
co mpletely ne w. The fork angle was
increased l o com pensate fo r the extra
rear end tra ve l. an d a ne w e xpan sio n
cha m ber w as fitt ed a ro und the new
sho ck jspring u nit. i\ sligh t inc rease in
weight , 216 pound, for th e 3 6 0 an d 21 3
pou nd s dr y wei ght for the 250. alo ng
wit h" sligh t ly high e r ce nt e r of gra vity .
wa s sacrificed in favo r o f the impro ved
sus pension.
A new dual clemen t
ai r cleaner
replaces the o lder YZ single ele men t
package.
l\Iol or cha nges were limited to a
minor re workin g o f the ports for a
rep orted in cr ease in to rq ue .
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