Yamaha YZF-R1(B) 2012 Service Manual

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Contents

ENGINE INSPECTION5-1EAS14B1052ENGINE INSPECTIONEAS14B1053MEASURING THE COMPRESSION PRES-SUREThe following procedure applies to all of thecylinders.TIPInsufficient compression pressure will result ina loss of performance.1. Measure:• Valve clearanceOut of specification → Adjust.Refer to “ADJUSTING THE VALVECLEARANCE” on page 3-5.2. Start the engine, warm it up for severalminutes, and then turn it off.3. Remove:• Fuel tankRefer to “FUEL TANK” on page 7-1.• Air filter caseRefer to “AIR FILTER CASE” on page 7-5.• Air filter case ductRefer to “AIR INDUCTION SYSTEM” onpage 7-21.4. Remove:• Ignition coils• Spark plugsECA13340Before removing the spark plugs, use com-pressed air to blow away any dirt accumu-lated in the spark plug wells to prevent itfrom falling into the cylinders.5. Install:• Compression gauge “1”6. Measure:• Compression pressureOut of specification → Refer to steps (c)and (d).▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼a. Set the main switch to “ON”.b. With the throttle wide open, crank theengine until the reading on the compres-sion gauge stabilizes.WARNINGEWA14B1017To prevent sparking the plug, remove allignition coil couplers before cranking theengine.TIPThe difference in compression pressurebetween cylinders should not exceed 100 kPa(1 kgf/cm², 14 psi).c. If the compression pressure is above themaximum specification, check the cylinderhead, valve surfaces and piston crown forcarbon deposits.Carbon deposits → Eliminate.d. If the compression pressure is below theminimum specification, pour a teaspoonfulof engine oil into the spark plug bore andmeasure again.Refer to the following table.Compression gauge90890-03081Engine compression testerYU-33223Standard compression pres-sure (at sea level)1480 kPa/350 r/min (14.8 kgf/cm²/350 r/min, 210.5 psi/350 r/min)Minimum–Maximum1290–1660 kPa/350 r/min(12.9–16.6 kgf/cm²/350 r/min,183.5–236.1 psi/350 r/min)