Problem: Engine noisy (Noise seems to come from timing chain) Condition Remedy 1. Chain stretched 1. Replace chain 2. Sprockets worn 2. Replace sprockets 3. Tension adjuster malfunctioning 3. Repair - replace adjuster Problem: Engine noisy (Noise seems to come from crankshaft) Condition Remedy 1. Bearing worn - burned 1. Replace bearing 2. Lower rod-end bearing worn - burned 2. Replace crankshaft 3. Connecting rod side clearance too large 3. Replace crankshaft Problem: Engine noisy (Noise seems to come from transmission) Condition Remedy 1. Gears worn - rubbing 1. Replace gears 2. Splines worn 2. Replace shaft(s) 3. Primary gears worn - rubbing 3. Replace gears 4. Bearings worn 4. Replace bearings 3 5. Bushing worn 5. Replace bushing Problem: Engine noisy (Noise seems to come from secondary bevel gear and final driven shaft) Condition Remedy 1. Drive - driven bevel gears damaged - worn 1. Replace gears 2. Backlash excessive 2. Adjust backlash 3. Tooth contact improper 3. Adjust contact 4. Bearing damaged 4. Replace bearing 5. Gears worn - rubbing 5. Replace gears 6. Splines worn 6. Replace shaft(s) 7. Final driven shaft thrust clearance too large 7. Replace thrust washer(s) Problem: Engine idles poorly Condition Remedy 1. Valve clearance out of adjustment 1. Adjust clearance 2. Valve seating poor 2. Replace - service seats - valves 3. Valve guides defective 3. Replace cylinder head 4. Rocker arms - arm shaft worn 4. Replace arms - shafts 5. Magneto defective 5. Replace magneto 6. CDI unit defective 6. Replace CDI unit 7. Spark plug fouled - gap too wide 7. Adjust gap - replace plug 8. Ignition coil defective 8. Replace ignition coil 9. Float out of adjustment 9. Adjust float height 10. Jets obstructed 10. Clean jets 11. Pilot screw setting improper 11. Adjust pilot screw 12. Fuel injector obstructed 12. Replace fuel injector 3-5