Polaris TRAIL BOSS 325 2001 Manual page 48

MAINTENANCE
DRIVE CHAIN ADJUSTMENT, CONCENTRIC SWINGARM
CAUTION: Never adjust or operate the vehicle with the rear drive chain too loose or too tight as severe
damage to the transmission and drive components can result.
Break-In: It is extremely important to maintain proper chain tension to ensure the best possible chain life. There is a chain
break-in period of approximately 100 miles or two (2) tanks of fuel. During this time chain tension should be watched
very closely and loads to the chain should be kept light.
Checking Deflection: Inspect chain deflection by slowly moving the ATV forward so any slack that may have
previously been on the under part of the chain is now on the top side of the chain. The bottom part of the chain
should be taught during inspection. Measure the chain deflection as shown in the diagram. Delfection should
be approximately 3/8, (10 mm). After inspection, again slowly move the ATV forward until all the chain slack is
on the top side of the chain and inspect the deflection. Repeat this procedure several times to check different
spots on the chain.
The chain is correctly adjusted when the tightest portion of the chain itself has approximately 3/8, (10 mm) of
deflection. It's a common characteristic of any chain to have one or more tight spots in the chain. Therefore, it
is extremely important to check chain deflection in several areas of the chain to ensure deflection is correct at
the tightest point.
ADJUSTMENT PROCEDURE - CONCENTRIC SWINGARM
1. Loosen chain guide.
2. Loosen the two (2) eccentric clamp bolts.
3. Loosen caliper mounting bracket bolts located
under the axle.
2.30
3/8s (10 mm) Deflection
Loosen Eccentric
clamp bolts (Step 2)
Loosen (2) caliper
mounting bracket
bolts (Step 3)