Cam Chain Adjustment; Spark Plug Heat Range; Spark Plug Removal - Polaris 1999 Sportsman 400 Service Manual

LUBRICATION, M AINTENANCE AND TUNE-U P
85
Spa r k Plug Heal Rauge
Spark pl ugs arc availabl e in various heat ra nges,
ho tter or co lder tha n the plu gs or igina lly insta lled.
Se lec t a plug of tile heat range desig ned for the
load s and con dit ions unde r which the ve hicle wi ll
he ope rate d.
In ge neral , use " hot plug for low speeds and low
tem peratures.
USC "
co ld plug for high spee ds, high
engine loa ds and
high
tem peratures. Th e
plug
sho uld o pera te hot eno ugh to bum off un want ed de-
po sits, but not so hot that
it
is damaged or causes
pre ign ition . A spar k plu g of the correct heat range
will
s how a lig ht tan co lor on
the
po rtion
of'the insu-
lator
w ithin
the
cy linde r
after
the plu g has been in
se rvice.
T he rea ch or leng th of a plug is
"' S O
imp ortan t. A
lon ger
than normal plug
could interfere w ith the
pis-
ton , ca using perma nent and severe da mag e ; re fer to
l1igure 85 .
Refer to Ta ble 6 for recommend ed spark plug
heat ran ges.
Too s hort
Correct
Too long
Spark Plug Remova l
6. Install a to rque wrenc h (C, Figure 84 ) ont o the
offse t adapter at a 90
0
angle and tighten the adj uste r
lockn ut to the torque spec ifica tio n listed in Tab le 5.
7. Recheck the clearance to make sure the adj uste rs
d id not move when the locknut wa s tig htened. Re-
adjus t the va lve clearance
if
nece ssary.
8. C lean the gasket su rfaces of the cylinder hea d
and cover, then ins tall a new gas ket to the cy linder
head cover (Figu re 83) .
9. Install the cylinde r head cover and tighten the re-
taining screws to the torque listed in Tab le 5.
10. Install all rema in ing compo nents removed.
C a m Chain Adj us t ment
The engin e is equi pped wi th an aut om atic cam
chain tension cr assembl y. No adjustment is po ssibl e
or req uired .
CAUTION
Whenever the spark plug is removed.
dirt aro und
it
can f all into the plug
hole. This
('Ull
cause serious engine
damage.
I. Remove the scat as described in Chapter Fifteen .
2. Remo ve the fuel tank as describ ed in Chapter Six.
3. Blow away a ll loose di rt then w ipe
off' the
cy lin-
der head. Remove nil loose deb ris that could fall
into the cy linder head spark plu g tunn el.
4 . Grasp the spark pl ug lead, twi st fro m
side-to-side to break the scal loose. Th en pull the
cap
off
the spa rk plug and o ut of the cyl inder head
(Fig ure 86). If the cap is stuck to the pl ug, twist it
slig htly to bre ak it loo se.
NO TE
Use
II
specia l spark plug socket
equipped with a rubber insert that
contac ts the side of the spark plug.
This t ype of soc ket is included in the
standard tool kit. It
is nece.'lsm :1' for
both removal and instal/ation since
the spark plug is recessed in the cy lin-
der head. The spark plug cannot be
removed or installed withlingers.