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Cert III Motorcycle Mech study materials
Cert III Motorcycle Mech study resources

Cert III Motorcycle Mech practice questions

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Question 1Core units

Which document is the primary reference for the correct lubricant grade and service interval for a customer's motorcycle?

  1. The customer's verbal preference
  2. The workshop manual for that model Correct answer.
  3. The tyre placard on the swingarm
  4. The general service checklist

Explanation

Manufacturer workshop manuals state the approved lubricant specifications and the scheduled service intervals for each model and variant. These figures are model-specific, so a generic checklist or a tyre placard cannot substitute for them. Always confirm the exact model and year before ordering lubricant or booking a service.

Question 2Core units

A technician is about to lift a motorcycle on a hydraulic bench. What is the first safety action before raising the machine?

  1. Loosen the axle nuts for later work
  2. Start the engine to check oil flow
  3. Remove the fuel tank to reduce weight
  4. Confirm the bike is secured to the bench and the area is clear Correct answer.

Explanation

Before any lift, the machine must be correctly restrained on the platform and the surrounding area cleared of people and obstructions. Weight reduction or preliminary disassembly is not part of the lifting procedure and can make the load unstable. Starting an engine on a raised bench is unsafe and unrelated to securing the load.

Question 3Core units

Which personal protective equipment is essential when using a compressed-air blowgun to clean a motorcycle component?

  1. A dust mask only
  2. Steel-capped boots only
  3. Safety glasses and hearing protection Correct answer.
  4. Cotton gloves only

Explanation

Compressed air can propel debris and metal particles into the eyes and generates high noise levels, so eye and hearing protection are both required. Other items may be useful but do not address the primary hazards of the task. Correct PPE selection is based on the specific hazard identified in the risk assessment.

Question 4Core units

Which unit is used to express the torque setting for a cylinder head bolt?

  1. Litres per minute
  2. Ohms
  3. Newton metres Correct answer.
  4. Kilopascals

Explanation

Torque is a rotational force measured in newton metres in the metric system. Kilopascals measure pressure, litres per minute measure flow, and ohms measure electrical resistance. Using the correct unit prevents over- or under-tightening of critical fasteners.

Question 5Core units

What does the abbreviation TDC mean when timing a motorcycle engine?

  1. Top dead centre, the highest point of piston travel Correct answer.
  2. Timing delay compensation, an ignition setting
  3. Thermal distribution curve, a cooling test
  4. Total drive clearance, the chain slack limit

Explanation

Top dead centre is the position where the piston reaches the highest point of its stroke in the cylinder. It is a key reference for valve timing and ignition timing marks. The other expansions are not standard engine terminology.

Question 6Core units

Which tool is the correct choice for removing a cross-head screw that is tight but undamaged?

  1. An adjustable wrench
  2. A cold chisel
  3. Multigrip pliers
  4. A screwdriver that fully engages the screw head Correct answer.

Explanation

A screwdriver of the correct tip size and type engages the full slot and transfers torque without damaging the head. Wrenches, chisels and pliers do not fit the recess and will round or split the head. Correct tool selection protects both the fastener and the component.

Question 7Core units

Why should a torque wrench be returned to its lowest setting after use?

  1. To stop the ratchet reversing direction
  2. To make the scale easier to read
  3. To preserve the accuracy of its internal spring Correct answer.
  4. To prevent the handle from rusting

Explanation

Leaving a torque wrench set at a high value keeps the internal spring compressed, which can cause it to lose calibration over time. Storing it at the lowest setting relieves that load and protects accuracy. Rust prevention and readability are not the reason for this practice.

Question 8Core units

In a four-stroke engine, which stroke follows the compression stroke?

  1. The intake stroke
  2. The exhaust stroke
  3. The power stroke Correct answer.
  4. The scavenging stroke

Explanation

The four-stroke cycle runs intake, compression, power and exhaust in that order. Ignition occurs at the end of compression, driving the piston down on the power stroke. Scavenging is a term used mainly for two-stroke operation.

Question 9Core units

A motorcycle's front brake lever feels spongy and travels close to the grip. Which condition most directly explains this?

  1. Air has entered the hydraulic brake system Correct answer.
  2. The tyre pressure is too high
  3. The clutch cable is over-lubricated
  4. The brake pads are new and thick

Explanation

Air is compressible, so bubbles in the hydraulic circuit absorb lever force and produce a spongy feel with excessive travel. Thick new pads reduce travel rather than increase it, and tyre pressure and clutch lubrication do not affect brake lever feel. The system should be bled and checked for leaks.

Question 10Core units

During a routine service, engine oil is drained and found to be milky and grey. What is the most likely cause?

  1. The oil filter is fitted too tightly
  2. The engine is running too cold
  3. The oil is simply due for replacement
  4. Coolant or water is mixing with the oil Correct answer.

Explanation

Milky, emulsified oil indicates water or coolant contamination, often from a failed head gasket, cracked casting or water pump seal. Normal used oil darkens but does not turn grey and cloudy. The cause must be found and repaired before fresh oil is added.

Question 11Core units

A customer reports the rear chain needs adjusting every few hundred kilometres. Which inspection is most appropriate first?

  1. Replace the spark plugs
  2. Check for tight spots and worn sprocket teeth Correct answer.
  3. Top up the brake fluid
  4. Increase tyre pressure to the maximum

Explanation

Frequent adjustment suggests the chain has tight spots, is stretched unevenly, or the sprockets are hooked and worn. Measuring slack at several points along the chain reveals tight spots, and the sprocket teeth should be checked for wear. Unrelated systems will not explain rapid chain slackening.

Question 12Core units

Why is it important to use the manufacturer's specified coolant type rather than a generic one?

  1. Specified coolant is cheaper to buy
  2. Coolant type only affects the radiator cap
  3. Generic coolant is always the wrong colour
  4. Different coolant chemistries can damage seals and alloy components Correct answer.

Explanation

Coolant formulations differ in their corrosion inhibitors and base chemistry, and the wrong type can attack seals, gaskets and aluminium or magnesium components. Colour alone is not a reliable indicator of compatibility. Following the manufacturer's specification protects the cooling system.

Question 13Core units

A motorcycle battery reads 12.4 volts at rest after sitting overnight. What does this indicate?

  1. The battery is partially discharged and should be charged or tested Correct answer.
  2. The battery has reversed polarity
  3. The battery is fully charged and healthy
  4. The charging system is overcharging

Explanation

A healthy, fully charged lead-acid battery at rest typically reads around 12.6 volts or slightly above. A reading of 12.4 volts indicates partial discharge, so the battery should be recharged and then load tested. Overcharging would show a higher charging voltage, and reversed polarity would read negative.

Question 14Core units

What is the purpose of setting valve clearance on an engine with mechanical tappets?

  1. To adjust the ignition timing
  2. To maintain correct valve timing and seating as parts expand with heat Correct answer.
  3. To reduce the oil pressure
  4. To increase the compression ratio

Explanation

Mechanical valve clearance allows for thermal expansion so valves still open fully and close completely when the engine is hot. Too little clearance can hold a valve open, while too much causes noise and reduced lift. Clearance does not set compression ratio, oil pressure or ignition timing.

Question 15Core units

Which measurement confirms that a brake disc is within service limits?

  1. Pad lining colour compared with a chart
  2. Disc diameter measured with a tape measure
  3. Disc thickness measured with a micrometer at several points Correct answer.
  4. Caliper bolt torque checked with a torque wrench

Explanation

Brake discs have a minimum thickness specification, and wear is checked with a micrometer at multiple points around the disc. This detects both general wear and thickness variation. Diameter, pad colour and bolt torque do not establish whether the disc is serviceable.

Question 16Core units

A tyre's sidewall marking reads 110/70 R17. What does the 70 represent?

  1. The load index of the tyre
  2. The rim diameter in inches
  3. The maximum speed rating
  4. The aspect ratio of sidewall height to section width Correct answer.

Explanation

In this size code the first number is section width in millimetres, the second is the aspect ratio as a percentage of width, and the last is rim diameter in inches. The aspect ratio therefore describes sidewall height relative to width. Load index and speed rating appear as separate letters and numbers.

Question 17Core units

When should a motorcycle's brake fluid be replaced according to typical manufacturer guidance?

  1. Only when the brake lever feels firm
  2. Only when the fluid looks clear
  3. Whenever the pads are replaced
  4. At the interval specified in the manual, often every one to two years Correct answer.

Explanation

Brake fluid is hygroscopic and absorbs moisture over time, which lowers its boiling point and promotes corrosion. Manufacturers therefore specify periodic replacement, commonly every one to two years, regardless of appearance. Lever feel and pad replacement are not reliable indicators of fluid condition.

Question 18Core units

Which factor most affects the choice of spark plug heat range for a given engine?

  1. The operating temperature the plug must dissipate under load Correct answer.
  2. The length of the battery cable
  3. The viscosity of the fork oil
  4. The colour of the ignition coil

Explanation

A spark plug's heat range describes how quickly it sheds heat, and the correct range keeps the insulator tip within a safe operating temperature under load. Plugs that run too hot can pre-ignite, while too cold a plug fouls. Ignition coil colour, cable length and fork oil have no bearing on plug heat range.

Question 19Core units

A motorcycle fitted with fuel injection idles roughly and the exhaust smells strongly of fuel. Which diagnosis is most consistent with these symptoms?

  1. The chain is too tight
  2. The coolant is too weak
  3. An injector is leaking or the fuel mixture is too rich Correct answer.
  4. The battery is undercharged

Explanation

A strong fuel smell with rough idling points to excess fuel entering the engine, such as a leaking injector or a rich mixture from faulty sensors. A lean condition would not produce a heavy fuel smell. Battery charge, chain tension and coolant strength do not cause these symptoms.

Question 20Core units

What is the main reason for measuring cylinder bore wear at several heights and in two directions?

  1. To determine the correct spark plug gap
  2. To set the valve clearance
  3. To calculate the engine's oil capacity
  4. To detect taper and out-of-round in the bore Correct answer.

Explanation

Cylinder wear is rarely uniform, so measuring at several heights reveals taper and measuring at right angles reveals out-of-round. Together these indicate whether the bore needs reboring or replacement. The measurements do not determine oil capacity, plug gap or valve clearance.

Question 21Core units

During a road test a motorcycle pulls to one side under steady braking. Which cause should be investigated first?

  1. A worn clutch friction plate
  2. An overfilled cooling system
  3. A loose exhaust clamp
  4. Unequal braking force between the front brake calipers or a sticking piston Correct answer.

Explanation

Pulling under braking indicates unequal braking force, often from a sticking caliper piston, contaminated pads or a partially seized slide. Brake force should be balanced across both sides of the front wheel. Cooling, clutch and exhaust faults do not cause directional pull under braking.

Question 22Core units

A technician must diagnose an intermittent electrical fault that only appears when the handlebars are turned. Which approach is most effective?

  1. Flex the wiring harness while monitoring the circuit with a meter Correct answer.
  2. Ignore the fault until it becomes permanent
  3. Replace every component in the circuit at once
  4. Increase the battery charging voltage

Explanation

Intermittent faults linked to handlebar movement usually indicate a broken wire or poor connector inside the harness. Flexing the harness while watching a meter or test lamp helps locate the exact point where continuity is lost. Parts substitution and raising voltage do not isolate the fault.

Question 23Core units

A four-cylinder engine has low compression on two adjacent cylinders and the cooling system is pressurising. What is the most likely explanation?

  1. Incorrect spark plug heat range
  2. A blocked air filter
  3. A failed head gasket between those cylinders Correct answer.
  4. Worn piston rings in all cylinders

Explanation

Low compression on two adjacent cylinders combined with cooling system pressurisation strongly suggests a head gasket failure breaching the fire ring between them. Combustion gas then enters the cooling system. Worn rings would affect all cylinders more evenly, and air filter or plug range faults do not pressurise the cooling system.

Question 24Core units

When balancing a wheel fitted with a new tyre, why is the valve stem often aligned with the tyre's light spot marking?

  1. To make the valve easier to reach
  2. To reduce the amount of balance weight required Correct answer.
  3. To improve the tyre's grip in the wet
  4. To increase the tyre's load rating

Explanation

The light spot marks the tyre's lightest point, and aligning it with the valve, often the heaviest point of the rim, offsets imbalance. This minimises the correction weight needed. Valve access, load rating and wet grip are unaffected by this alignment.

Question 25Core units

A motorcycle's suspension sag is measured with the rider aboard and found to be excessive at the rear. What does this indicate?

  1. The steering head bearing is loose
  2. Spring preload or spring rate is insufficient for the load Correct answer.
  3. The tyre is over-inflated
  4. Rebound damping is set too firm

Explanation

Rider sag measures how far the suspension compresses under the rider's weight, and excessive sag means the spring is too soft or preload is too low for that load. Damping settings control the speed of movement, not static ride height. Tyre pressure and steering bearings do not set sag.

Question 26Core units

Which document should a technician consult first to find the correct engine oil viscosity and specification for a specific motorcycle model?

  1. A generic oil container label
  2. The owner's or workshop manual for that model Correct answer.
  3. A tyre pressure placard on the swingarm
  4. The parts catalogue illustration index

Explanation

The manufacturer's manual for the specific model lists the approved oil grade, viscosity and specification, and it accounts for engine design and climate recommendations. Generic labels and unrelated placards do not define the requirement for a given engine.

Question 27Core units

What is the primary purpose of a pre-start safety check before riding a customer's motorcycle into the workshop?

  1. To test the battery's cranking capacity under load
  2. To warm the engine to full operating temperature
  3. To verify the odometer reading for the invoice
  4. To confirm brakes, tyres and controls function before moving the machine Correct answer.

Explanation

A pre-start check confirms that the machine can be moved safely, covering brakes, tyre condition and pressure, steering, throttle operation and fluid leaks. Warming the engine, billing data and battery testing are separate tasks performed later.

Question 28Core units

A technician is about to lift a motorcycle on a hydraulic bench. Which practice best protects both the technician and the machine?

  1. Support the machine under the exhaust headers
  2. Secure the frame or sump with rated straps and check the lift locks engage Correct answer.
  3. Raise the bench fully before positioning the bike
  4. Leave the sidestand down to add a third contact point

Explanation

Rated straps attached to strong frame points plus engaged mechanical locks prevent the machine shifting or the bench creeping down. Exhaust headers and a deployed sidestand are not load-bearing supports and can be damaged or fold unexpectedly.

Question 29Core units

Which unit is used to express fastener tightening torque in metric motorcycle service data?

  1. Ampere hours
  2. Kilopascals
  3. Newton metres Correct answer.
  4. Lumens

Explanation

Torque is a rotational force expressed in newton metres in metric specifications. Kilopascals measure pressure, lumens measure light output and ampere hours measure battery capacity.

Question 30Core units

What does the first number in a multigrade oil designation such as 10W-40 indicate?

  1. The oil's total additive concentration
  2. The oil's flash point in degrees Celsius
  3. The oil's viscosity at full operating temperature
  4. The oil's viscosity behaviour at low temperature Correct answer.

Explanation

The number before the W describes cold-temperature viscosity behaviour, indicating how readily the oil flows when cold. The second number describes viscosity at operating temperature. Additive levels and flash point are not represented in the grade.

Question 31Core units

A technician must dispose of drained engine oil and used oil filters. Which approach meets typical environmental obligations?

  1. Mix the oil with general rubbish for landfill
  2. Store the oil in an open drum indefinitely
  3. Place oil and filters in the designated waste-oil collection system for recycling Correct answer.
  4. Pour the oil onto gravel behind the workshop

Explanation

Used oil is a regulated waste that must go to an approved collection or recycling stream, and filters are drained and processed separately. Dumping, mixing with general waste or open storage creates pollution and legal liability.

Question 32Core units

Which personal protective item is most important when using a compressed-air blowgun to dry components?

  1. Heavy leather welding gloves
  2. Eye protection and reduced nozzle pressure Correct answer.
  3. A full-face welding shield
  4. Cotton overalls without fastenings

Explanation

Airborne debris and fluid droplets can injure eyes, so sealed goggles and regulated nozzle pressure are the key controls. Welding gloves and a welding shield address hot-work hazards, not airblast debris.

Question 33Core units

What is the main function of the clutch in a manual-transmission motorcycle?

  1. To multiply engine torque at the rear wheel
  2. To maintain constant chain tension as the suspension moves
  3. To limit maximum engine speed electronically
  4. To progressively connect and disconnect engine drive to the gearbox Correct answer.

Explanation

The clutch uses friction to engage drive smoothly from standstill and to interrupt drive for gear changes. Speed limiting, torque multiplication and chain tension control are functions of other systems.

Question 34Core units

A customer's motorcycle has a hydraulic disc brake at the front and a drum brake at the rear. Which statement correctly describes a routine inspection point for the drum brake?

  1. Renew the rear brake pads
  2. Check the wear indicator and the condition of the shoes and drum surface Correct answer.
  3. Measure the brake fluid level in the rear reservoir
  4. Bleed air from the rear caliper

Explanation

A drum brake is checked through its wear indicator, shoe lining thickness and drum condition rather than hydraulic components. Fluid reservoirs, caliper bleeding and pads belong to a disc system.

Question 35Core units

During a compression test on a warm engine, one cylinder reads noticeably lower than the others, but adding a small amount of oil to that cylinder raises the reading. What does this indicate?

  1. A blown head gasket between cylinders
  2. Worn piston rings or bore allowing blow-by past the piston Correct answer.
  3. A leaking exhaust valve seat
  4. Incorrect valve clearance on that cylinder

Explanation

Oil temporarily seals the ring-to-bore gap, so a rise after oiling points to ring or bore wear. Valve and gasket faults are not sealed by oil in the same way.

Question 36Core units

A motorcycle's charging system output is measured at the battery terminals. Which result best indicates the regulator-rectifier is charging correctly at raised engine speed?

  1. Approximately 16.5 volts
  2. Approximately 10.5 volts
  3. Approximately 13.8 to 14.5 volts Correct answer.
  4. Approximately 12.0 volts

Explanation

A healthy charging system holds the battery near 14 volts at raised engine speed, which is enough to recharge without overcharging. Readings near resting voltage indicate no charge, and very high readings indicate regulation failure.

Question 37Core units

A rear tyre shows a band of severe wear on one side of the tread while the opposite side is relatively unworn. Which cause should be investigated first?

  1. Under-inflation across the whole tyre
  2. Wheel misalignment or incorrect fitment in the swingarm Correct answer.
  3. Incorrect spark plug heat range
  4. A seized front brake caliper

Explanation

Asymmetric wear across the tread usually indicates the wheel is not running true with the machine, from misalignment or incorrect fitment. Uniform under-inflation causes wear on both shoulders, and unrelated systems do not cause this pattern.

Question 38Core units

When adjusting steering head bearings, what is the correct method for setting bearing preload?

  1. Leave the adjuster loose so the bearings self-centre in service
  2. Set the bearings so the bars fall freely to both sides under their own weight
  3. Tighten fully until the steering will not turn, then back off one full turn
  4. Tighten to the specified procedure and check for free play and smooth movement without binding Correct answer.

Explanation

Preload must follow the manufacturer's sequence and then be verified by checking for play and for smooth, unbound movement through the full arc. Overtightening damages races, and a completely free fall indicates insufficient preload.

Question 39Core units

A technician is setting up a multimeter to check for excessive current draw on a battery with everything switched off. Which meter setting is appropriate?

  1. DC volts, with the meter connected across the battery
  2. DC current, with the meter connected in series in the circuit Correct answer.
  3. Resistance, with the meter connected across the battery
  4. AC volts, with the meter connected to the frame

Explanation

Measuring current requires the meter to be placed in series so the circuit current flows through it, with the correct DC current range selected. Voltage is measured in parallel, and resistance must not be measured on a live circuit.

Question 40Core units

Why is it important to check that a replacement battery has the same case dimensions and terminal layout as the original?

  1. To raise the cold cranking rating of the machine
  2. To increase the charging voltage available to the system
  3. To reduce the current draw of the starter motor
  4. To ensure it secures correctly and the cables reach the correct terminals Correct answer.

Explanation

Physical fit and terminal orientation determine whether the battery clamps securely and whether cables can reach without strain or reversed polarity. Case size does not change charging voltage, current draw or cranking rating.

Question 41Core units

A motorcycle with telescopic forks dives excessively under braking and feels harsh over small bumps. Which component is most directly implicated?

  1. Fork springs and damping oil condition Correct answer.
  2. Steering head bearing preload
  3. Rear shock spring preload
  4. Front brake pad compound

Explanation

Excessive dive and harshness at the front are governed by fork spring rate, oil level and damping performance. Rear preload, steering bearings and pad compound do not control fork travel behaviour.

Question 42Core units

What is the correct action when a torque wrench has been dropped onto a hard floor?

  1. Withdraw it from service and have its calibration verified Correct answer.
  2. Oil the mechanism and return it to the toolboard
  3. Use it only for low-torque fasteners
  4. Continue using it but add ten per cent to the setting

Explanation

A dropped torque wrench may have lost calibration or suffered internal damage, so it must be checked before further use. Adjusting settings or restricting use does not restore confidence in its accuracy.

Question 43Core units

A customer complains that the neutral indicator lamp stays on in every gear. Which area should be checked first?

  1. The ignition coil primary resistance
  2. The headlamp relay
  3. The regulator-rectifier output
  4. The neutral switch circuit and its earth path Correct answer.

Explanation

A lamp lit in all gears suggests the neutral switch is stuck, shorted or poorly earthed so the circuit is permanently completed. Headlamp, charging and ignition components do not control the neutral indicator.

Question 44Core units

When replacing a chain and sprockets, why should both sprockets normally be renewed with the chain?

  1. Old sprockets reduce the need for lubrication
  2. Worn sprocket teeth accelerate wear of a new chain Correct answer.
  3. Sprocket renewal changes the final drive ratio
  4. New sprockets increase engine power output

Explanation

Worn sprocket profiles no longer match the new chain's pitch, so the chain wears and may ride high on the teeth. Renewing the set together preserves service life and does not alter power or ratio.

Question 45Core units

Which procedure correctly checks the operation of a motorcycle's engine kill switch?

  1. Measure the switch resistance with the engine running
  2. Disconnect the battery and observe the switch continuity only
  3. Start the engine and operate the switch to confirm the engine stops and restarts Correct answer.
  4. Bridge the switch terminals with a screwdriver

Explanation

The kill switch must be verified functionally by confirming it stops a running engine and allows restart. Static continuity checks alone do not prove the circuit interrupts ignition under running conditions.

Question 46Core units

A four-stroke engine's valve clearance is found to be tighter than specification on one intake valve. What is the most likely consequence if left uncorrected?

  1. The valve will open later and reduce lift duration only
  2. The valve may not seat fully, leading to compression loss and possible burning Correct answer.
  3. The camshaft will rotate more slowly at high speed
  4. Oil consumption will fall because the guide seals better

Explanation

Insufficient clearance holds the valve off its seat during the compression and power strokes, causing leakage, overheating and eventual valve damage. Reduced clearance does not improve sealing or slow the camshaft.

Question 47Core units

A motorcycle with electronic fuel injection shows a steady high idle that does not respond to the throttle. Which diagnostic step is most appropriate first?

  1. Adjust the throttle cable free play only
  2. Read stored fault codes and check live data for throttle position and coolant temperature Correct answer.
  3. Renew all four spark plugs
  4. Replace the fuel pump immediately

Explanation

Electronic systems store codes and stream live sensor data, which identifies whether the throttle position or coolant temperature signal is misleading the ECU. Parts substitution or cable adjustment without data risks missing the real cause.

Question 48Core units

During a road test, a motorcycle's front wheel shudders only when the brake is applied lightly at low speed. Which inspection is most likely to reveal the cause?

  1. Check the rear shock rebound damping
  2. Check the battery voltage under load
  3. Check the chain slack measurement
  4. Check the disc for lateral runout and thickness variation Correct answer.

Explanation

Low-speed brake shudder usually comes from disc runout or uneven thickness, which creates pulsing at the pads. Rear damping, chain slack and battery condition do not produce brake-dependent front vibration.

Question 49Core units

A technician is diagnosing a motorcycle that intermittently loses all electrical power while riding over rough surfaces. Which approach best isolates the fault?

  1. Measure alternator output at idle only
  2. Replace the battery and retest on a smooth road
  3. Check tyre pressures and wheel balance
  4. Perform a voltage-drop test across earth and supply paths while flexing the harness Correct answer.

Explanation

Intermittent power loss over bumps points to a loose connection or chafed conductor, so voltage-drop testing while moving the harness reveals the high-resistance point. Static testing or unrelated checks will not reproduce the fault.

Question 50Core units

A motorcycle's engine oil level is checked with the machine on its sidestand. Why does this give an unreliable reading?

  1. The oil is too hot to measure accurately
  2. The dipstick cannot reach the oil when tilted
  3. The machine is not level, so oil is not distributed correctly in the sump Correct answer.
  4. The oil pump stops circulating when the machine is tilted

Explanation

Oil level must be checked with the machine upright and level so the sump and dipstick relationship matches the manufacturer's specification. Tilt moves oil away from the dipstick and produces a false reading.