3
9928485 R01 - 2017-2018 RANGER 500 / 570 Service Manual
© Copyright Polaris Industries Inc.
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2. Measure the height of each cam lobe from the base
circle to highest point on the lobe using a micrometer.
Compare to specification.
NOTE
Replace camshaft if damaged or if any part is worn past
the service limit.
MEASUREMENT
Camshaft Lobe Height:
Intake: 2.0327" ± 0.0038" (51.63 ± 0.097 mm)
Exhaust: 2.0657" ± 0.0038" (52.47 ± 0.097 mm)
EXHAUST CAMSHAFT DECOMPRESSION
MECHANISM
NOTE
Removal of the decompression mechanism is not
necessary unless replacement is required.
1. Thoroughly clean and inspect the decompression
mechanism
q
located on the exhaust camshaft.
2. Replace the decompression assembly if any
excessive wear or binding is evident.
3. Be sure the decompression mechanism functions
smoothly and easily returns under spring pressure to
the resting position against gravity.
NOTE
If the ball or bushing are damaged the whole camshaft
needs to be replaced. If there is damage to the weight,
spring, or shaft, the service kit 2206632 can be ordered
to replace the assembly.
CAM CHAIN AND GUIDE SERVICE
NOTE
The crankcase has a removable lower cam chain drive
guide that prevents the chain from disengaging the
crankshaft during engine service.
The cam chain, cam chain guides and cam chain
tensioner can be replaced with the engine installed in
the vehicle.
1. If not already performed, remove the valve cover,
stator cover, flywheel, cam chain tensioner, cam
carrier and camshafts as outlined in this chapter.
2. Remove the two fasteners
q
that secure the upper
cam chain guides
w
to the crankcase.
3. Remove the fasteners
e
that secure the lower cam
chain guide
r
to the crankcase.
4. Inspect the cam chain guides and replace if
excessive wear is evident.
ENGINE / COOLING SYSTEM