Engine Idles Poorly; Problem: Engine Runs Poorly At High Speed; Problem: Exhaust Smoke Dirty Or Heavy - Arctic Cat 450 XC 2011 Service Manual

Problem: Engine noisy (Noise seems to come from transmission)
Condition
1. Gears worn - rubbing
2. Splines worn
3. Primary gears worn - rubbing
4. Bearings worn
5. Bushing worn
Problem: Engine noisy (Noise seems to come from secondary bevel gear and final driven shaft)
Condition
1. Drive - driven bevel gears damaged - worn
2. Backlash excessive
3. Tooth contact improper
4. Bearing damaged
5. Gears worn - rubbing
6. Splines worn
7. Final driven shaft thrust clearance too large
Problem: Engine idles poorly
Condition
1. Valve clearance out of adjustment
2. Valve seating poor
3. Valve guides defective
4. Rocker arms - arm shaft worn
5. Crankshaft position sensor defective
6. ECU defective
7. Spark plug fouled - gap too wide
8. Ignition coil defective
9. Idle Step Control (ISC) malfunction

Problem: Engine runs poorly at high speed

Condition
1. High RPM "cut out" against RPM limiter
2. Valve springs weak
3. Valve timing incorrect
4. Cam - rocker arms - tappets worn
5. Spark plug gap too narrow
6. Ignition coil defective
7. Air cleaner element obstructed
8. Fuel hose obstructed
9. Fuel pump defective

Problem: Exhaust smoke dirty or heavy

Condition
1. Oil (in the engine) overfilled - contaminated
2. Piston rings - cylinder worn
3. Valve guides worn
4. Cylinder wall scored - scuffed
5. Valve stems worn
6. Stem seals defective
Remedy
1. Replace gears
2. Replace shaft(s)
3. Replace gears
4. Replace bearings
5. Replace bushing
Remedy
1. Replace gears
2. Adjust backlash
3. Adjust contact
4. Replace bearing
5. Replace gears
6. Replace shaft(s)
7. Replace thrust washer(s)
Remedy
1. Adjust clearance
2. Replace - cylinder head - valves
3. Replace cylinder head
4. Replace arms - shafts
5. Replace stator assembly
6. Replace ECU
7. Adjust gap - replace plug
8. Replace ignition coil
9. Replace ISC
Remedy
1. Shift into higher gear - decrease speed
2. Replace springs
3. Correct timing - check chain, sprockets, and cam chain ten-
sioner
4. Replace cam - arms - tappets
5. Adjust gap
6. Replace ignition coil
7. Clean element
8. Clean or replace hose
9. Replace fuel pump
Remedy
1. Drain excess oil - replace oil
2. Replace - service rings - cylinder
3. Replace cylinder head
4. Replace - service cylinder
5. Replace valves
6. Replace seals
Manual
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