Yamaha YZ125 Owner's Manual

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ENGINE3-6NOTICEECA13330Before removing the spark plug, blow awayany dirt accumulated in the spark plug wellwith compressed air to prevent it from fallinginto the cylinder.3. Check:• Spark plug typeIncorrect  Change.4. Check:• Electrode “1”Damage/wear  Replace the spark plug.• Insulator “2”Abnormal color  Replace the spark plug.Normal color is medium-to-light tan.5. Clean:• Spark plug(with a spark plug cleaner or wire brush)6. Measure:• Spark plug gap “a”(with a wire thickness gauge)Out of specification  Regap.7. Install:• Spark plugTIPBefore installing the spark plug, clean the sparkplug and gasket surface.8. Connect:• Spark plug capEAM30539CHECKING THE TRANSMISSION OIL LEVEL1. Start the engine, warm it up for several min-utes and wait for five minutes.2. Place the machine on a level place and holdit up on upright position by placing the main-tenance stand under the engine.3. Check:• Transmission oil levela. Remove the oil check bolt “1”.b. Inspect the oil level.TIPBe sure the machine is positioned straight upwhen inspecting the oil level.WARNINGEWA21090Never attempt to remove the oil check boltjust after high speed operation. The heatedoil could spout out, causing danger. Wait un-til the oil cools down.Oil flows out  Oil level is correct.Oil does not flow out  Oil level is low.Add transmission oil until oil flows out.c. Inspect the gasket (oil check bolt), replaceif damaged.d. Tighten the oil check bolt.EAM30540CHANGING THE TRANSMISSION OIL1. Start the engine and warm it up for severalminutes and wait for five minute.2. Place the machine on a level place and holdit on upright position by placing the mainte-nance stand under the engine.3. Place a suitable container under the engine.Manufacturer/modelNGK/BR9EVXSpark plug gap0.6–0.7 mm (0.024–0.028 in)Spark plug20 N·m (2.0 kgf·m, 15 lb·ft)G088879T R..TypeMotor oil SAE 10W-40 type SG orhigherQuantity (disassembled)0.70 L (0.74 US qt, 0.62 Imp.qt)Quantity0.66 L (0.70 US qt, 0.58 Imp.qt)Oil check bolt10 N·m (1.0 kgf·m, 7.4 lb·ft)T R. .