Precision Measuring Tools; Feeler Gauge; Vernier Caliper, Dial Caliper And Digital Electronic Caliper; Outside Micrometers - Polaris 1999 Sportsman 400 Service Manual

G ENE RA L INFORM AT IO N
®
surfaces, always place a piece of woo d betwe en the
jack pad and the supported co mpon ent.
PREC ISIO N l\IEAS URl:O;G TOOLS
Measurement is an important part of engine and
suspension service. When per formi ng many of the
service procedures in this manual, a number of
measurements are required. These include basic
checks such as engine compression and spark plug
gap. As shop ex perie nce progresses into engine
disassembly and service. many measurements arc
required to determine the size and condition
of the
piston and cylinderbore and crankshaft runout
and
other co mplex measurement s.
When
making these
measurements, the degree of accurac y wi ll dictate
which tool is required. Precision measuring tools
arc expensive. If this is the first experience at en-
gine or suspension service, it may be more wo rth -
whi le to have the checks and measurements
performed by a Polaris dealership. a co mpetent in-
dependent vehicle repair shop or a machine shop.
However, as skills and enthusiasm increase for
do-
ing service work,
it
may be desirab le
10
buy some
15
of these spec iali zed too ls. The follow ing is a
description o ft he measuring tools required
to
per-
form the service procedures described in the vari-
ous chapters in this manual.
Feeler GauJ.:c
Feeler gauges come in assorted sets and types
(Fig ure 20 ). The feeler gauge is mad e of either a
piece ofa nat or round hardened steel ofa spec ified
thickness. Wire gauges are used
to
measure spark
plug gap. Flat gauges arc used for other measure-
ments. Feeler gauges are also designed for special-
ized uses. For example. the end
of a
gauge can be
small and angled to facilitate check ing valve cle ar-
ances on models requiring adjustment.
Ver nier C alipe r, Dia l C aliper and
Digital Electro nic C aliper
These arc valuable tools for reading inside, out-
side and depth measurements. Although this type of
tool is not as prec ise as a micrometer. it allows rea-
sonable, non-close tole rance measurements, typi-
cally to w ithin 0.025 mrn (0.00 1 in.). Common uses
of a vern ier caliper arc measuring the length of the
cl utch springs, the thickness of clutch plates. shims
and thrust washers, brake pad or lining thickness or
the dcpth of a bearing borc. The jaws of the ca liper
must be c1can and frcc of burrs at all times to obtain
an accurate measurement. There are several types
of vernier calipers available.
The
standard vernier
ca liper has a highly accurate graduated scale on the
handl e (Figure 21) in which the measurements
must be calc ulated, follow ing the manufacturer's
instructions. Th e dial indicator ca liper is equipped
with a small dia l and needle that indicates the mea-
surement reading; the digital electronic type has an
LCD display that shows thc measurement
Oil
thc
small display screen. Some vern iercalipers must be
calibrated prior to making a measurement to ensure
accuracy. Refer to the manufacturer's instructions
for this procedure.
Outside l\l icrometcrs
An outside micrometer is a precision tool used to
accurately measure parts using the decimal divi-
sio ns of the inch or meter (Figu re 22). Wh ile there
are many types and styles of micrometers. this sec-