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Details on engine specifications, technical data, and SI unit conversions.
Description of the SACHS 501/4 AKF engine variant with intake silencer.
Description of the SACHS 501/4 AKF X engine variant with intake silencer.
Description of SACHS 501/3 BKF, 501/4 BKF with grey-cast cylinder.
Description of SACHS 501/3 BF, 501/4 BF suitable for pedal start.
Detailed technical specifications for SACHS 501/4 AKF and AKF X models.
Detailed technical specifications for SACHS 501/3 BKF and 501/4 BKF models.
Detailed technical specifications for SACHS 501/3 BF and 501/4 BF models.
List of repair tools with part numbers and descriptions for engine rebuilding.
Procedure for draining the oil from the gearbox.
Instructions for securing the engine onto a repair jig for disassembly.
Steps for removing the carburettor from the engine assembly.
Procedure for removing the crankcase cover on the magneto side.
Steps for removing the drive sprocket and chain assembly.
Instructions for removing the sprocket, checking chain alignment.
Procedure for removing the flywheel using specific tools.
Detailed steps for removing the magneto flywheel and related parts.
Procedure for removing the stator plate and its components.
Instructions for removing the cylinder head and cylinder.
Steps for removing the piston and gudgeon pin.
Procedure for removing clutch side cover and layshaft gear.
Steps for removing the drive pinion and related parts.
Detailed procedure for dismantling the clutch assembly.
Instructions for dismantling the selector rod with a threaded end.
Instructions for dismantling the selector rod without a threaded end.
Instructions for re-mounting the engine block onto the repair jig.
Procedure for separating the engine block halves.
Steps for removing gearbox components like starter gear and shims.
Instructions for removing the crankshaft after heating the crankcase.
Procedure for removing the kickstarter mechanism from the crankcase.
Procedure for replacing leaky or damaged oil seals without engine dismantling.
Instructions for replacing bearings and outer races in crankcase halves.
Steps for pre-assembling the magneto-side crankcase half with seals.
Procedure for pressing in the crankshaft oil seal and ball bearing.
Instructions for pressing in the main shaft oil seal and ball bearing.
Procedure for replacing the bronze bush in the layshaft bearing.
Procedure for measuring and compensating crankshaft axial play.
Steps for assembling the crankshaft with bearings and support plate.
Instructions for pre-assembling the clutch-side crankcase half.
Procedure for removing and installing the gear change lever and related parts.
Guidance on carburettor adjustment, mixture control, and common issues.
Procedure for replacing ignition, generating, stop light, and taillight armatures.
Instructions for replacing the contact breaker set and associated parts.
Steps for desoldering, removing, and refitting the condenser.
Instructions for fitting the pedal shaft components and spring.
Steps for dismantling the selector assembly and its components.
Instructions for assembling the selector assembly with correct clearances.
Procedure for cleaning carbon deposits from the exhaust system.
Instructions for removing carbon deposits from cylinder head and ports.
Guidance on carefully removing carbon deposits from the piston crown.
Procedure for extracting the small end bush using special tools.
Instructions for installing a new small end bush with proper alignment.
Steps for reaming the small end bush to the correct diameter.
Procedure for measuring and compensating main shaft axial play.
Procedure for measuring and compensating kickstarter shaft axial play.
Instructions for installing the kickstarter mechanism onto the engine crankcase.
Procedure for measuring and compensating pedal shaft device axial play.
Procedure for adjusting the selector rod for proper gear engagement.
Instructions for fitting the drive sprocket, locking plate, and clutch components.
Procedure for fitting the clutch basket, springs, and pressure plates.
Procedure for measuring and compensating selector shaft axial play.
Procedure for installing the piston into the cylinder, ensuring proper alignment.
Instructions for installing the cylinder and cylinder head with correct tightening sequence.
Detailed steps for setting the ignition timing using timing marks and gauges.
Procedure for measuring and marking TDC and firing points if missing.
Instructions for installing the carburettor onto the intake manifold.
Procedure for fitting the magneto-side crankcase cover and ensuring speedometer drive engagement.
Instructions for filling the gearbox with the correct type and quantity of oil.
Procedure for routing and lubricating control cables before engine installation.
Steps for installing the engine into the vehicle frame.
Procedure for fitting the drive chain and ensuring correct tension.
Information on installing throttle and choke control cables.
Procedure for adjusting the clutch cable and lever for proper operation.
Steps for adjusting the carburettor for optimal performance on a warm engine.
Diagram showing terminals, wiring colours, and connections for the magneto-generator.
Procedure for preserving the engine for long-term storage to prevent rust and resinification.
Recommendations for spark plug cleaning, gap adjustment, and replacement intervals.
Procedure for lubricating the speedometer drive with grease.
Instructions for checking and changing the engine oil level.
Guidance on lubricating control cables and their associated parts.
Procedure for cleaning the fuel strainer.
Instructions for cleaning the intake manifold and bellows.
Procedure for cleaning and lubricating the drive chain.
Instructions for cleaning the carburettor and its components.
List of recommended sealants, greases, and oils for engine assembly.
Instructions for modifying the magneto housing for improved ventilation.
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General