Husqvarna 241R Workshop Manual Download Page 53

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Crankshaft and crankcase

Assembly

Mount the bearings in the crankcase
halves.

Inspect the small end of the connecting
rod.

Inspecting the crankshaft

Inspect the large end of the connecting
rod.

Check the crank bearing.

Assembly

Mount the bearings in the crankcase
halves.

Heat the crankcase halves to approx.
110°C using a hot air gun. Put the ball-
bearings in position.

Use a suitable punch and hammer, if
needed.

Inspect the small end of the connecting
rod.

If seizure marks or discolouration are
found in the bearing track the crankshaft
must be replaced.

Inspecting the
crankshaft

The crankshaft cannot be reconditio-
ned but must be replaced if it is worn or
damaged.

Inspect the large end of the connecting
rod. If seizure marks, discolouration on
the sides or damaged needle holders are
found the crankshaft must be replaced.

Check the crank bearing. The connecting
rod shall not have any radial play (up and
down).

It should, however, have axial play, in or-
der to ensure good lubrication of the crank
bearing among other things.

Summary of Contents for 241R

Page 1: ...Workshop manual 241R 241RJ English ...

Page 2: ...__________________________ 7 3 Fuel system ______________________________ 13 4 Centrifugal clutch__________________________ 29 5 Angle gear _______________________________ 35 6 Cylinder and piston ________________________ 39 7 Crankshaft and crankcase___________________ 49 8 Tools ___________________________________ 55 9 Technical Data____________________________ 59 Husqvarna AB Sweden 2008 ...

Page 3: ...een dismantled The sensitive sealing lip can easily be damaged resulting in inferior sealing capacity Surfaces which the seal shall seal against must also be completely undamaged Lubricate the sealing lip with grease before it is fitted and ensure that it is not damaged e g by shoulders and splines on a shaft Use tape or a conical sleeve as protection It is important that the sealing ring faces in...

Page 4: ...Starter 1 3 1 Starter Contents Dismantling ___________________________________ 4 Assembly_____________________________________ 5 Replacing the drive dogs_________________________ 6 ...

Page 5: ... the starter can be lifted out The cylinder cover does not need to be loosened or detached NOTE Ensure the bushings that guide the starter towards the fuel tank are not lost Remove the bolt in the centre of the star ter pulley and remove the starter pulley Remove the bolt in the centre of the star ter pulley Lift the starter pulley carefully from the starter cover Loosen the spring tension Loosen ...

Page 6: ...semble the starter handle Assemble the starter handle Tie a double knot on the starter cord and fold under the free end Pull the knot fully into the handle Tension the return spring Check the spring tension Tension the return spring Pull out the starter cord completely and slow the starter pulley with your thumb Lift the starter cord up out of the cut out on the starter pulley Now turn the starter...

Page 7: ...springs if necessary Remove the circlip holdings the drive dog Lift out the drive dog and spring for repla cement Assemble in the reverse order as set out for dismantling Check that the drive dogs move easily Replacing the drive dogs Dismantle the drive body Replacing the drive dogs Fit the puller 502 51 49 01 on the flywheel see chapter 2 Electrical system and loosen the drive cup NOTE The nut is...

Page 8: ...2 7 2 Electrical system Electrical system Contents Checking the ignition spark ___________________10 Dismantling _______________________________12 Assembly_________________________________14 ...

Page 9: ...Check the electrode gap It should be 0 5 mm Adjust the gap as needed to the correct value with the side electrode If the electrodes are worn more than 50 the spark plug should be changed If the electrodes are worn more than 50 the spark plug should be changed Too large a spark gap entails a great deal of stress on the ignition module and risk for short circuiting Check if a spark occurs when attem...

Page 10: ...n coil Use pliers no 502 50 06 01 to make a hole in the ignition lead When a part of the ignition lead has been cut off it helps to use the pliers no 502 50 06 01 to make a hole in the igni tion lead to fit the contact coil NOTE It is important that the tip of the contact coil hits the centre of the ignition lead to prevent sparking Attach the ignition coil to the ignition cable Attach the ignitio...

Page 11: ...ck if cable breakage has occurred due to pinching for example Adjust the air gap Adjust the air gap as needed to the cor rect value Loosen the bolts Position the feeler gauge and press the ignition module against the fly wheel Tighten the bolts and check the air gap again If the spark plug still does not fire the ignition system should be replaced Dismantling Dismantle the air filter cowling spark...

Page 12: ...ut the ignition lead and short circuit cables from their guides Remove the 3 screws E and swing the engine body to one side so the clutch becomes accessible Remove the nut holding the flywheel Remove the nut holding the flywheel Fit the puller on the flywheel Loosen and remove the nut Dismantle the ignition module and the centrifugal clutch Remove the remaining screws A holding the ignition module...

Page 13: ...semble the ignition module part number 501 31 98 01 Adjust the air gap It should be 0 3 mm between the permanent magnets in the flywheel and the ignition module Tighten the screws and do not forget the ring cable lug under the outer screw Assemble other parts in the reverse order as set out for dismantling NOTE Do not forget the rubber bushings between the fuel tank and the crankcase clutch cover ...

Page 14: ...5 Fuel filter _________________________________15 Fuel pump ________________________________16 Carburettor _______________________________16 Throttle handle model RJ ___________________ 23 Throttle handle model R ____________________ 24 Start throttle speed ________________________ 25 Carburettor settings________________________ 25 ...

Page 15: ...eaning agent before it is impregnated with air filter oil Air filter Dismantle the air filter cowling Remove the air filter and clean it in warm soapy water A damaged filter should be replaced with a new filter Air filter Dismantle the air filter cowling by loose ning the quick clasps and lift off the air filter The filter is manufactured of foamed plastic and should be cleaned in tepid soapy wate...

Page 16: ...nd mount the fuel cap in the reverse order to how it was disassembled Make sure that the flat surface on the co ver D is turned towards the diaphragm NOTE There is a small slit F in the diaphragm B that becomes visible when you carefully pull the edges of the diaphragm Check that the edges of the slit are not damaged Replace diaphragm if necessary Tank venting Check that the tank venting valve wor...

Page 17: ...rburettor Dismantling Blow the carburettor compartment clean and remove the nuts and the screw which hold the carburettor and air filter housing Carburettor Dismantling 1 Remove the air filter cover and cylinder cover and blow the carburettor compartment clean with compressed air 2 Remove the nuts and screw which hold the carburettor and air filter housing NOTE Do not lose the washer under the hea...

Page 18: ...the carburettor s function The blending unit Fuel and air are mixed here The blending unit In this section of the carburettor fuel and air are mixed in the proper proportions The choke and throttle valves are placed here In the middle of the venturi narrowest part of the throughput the main jet D is found The pump unit Pumps fuel from the tank to the carburet tor The pump unit This is where the pu...

Page 19: ...r on the pin C Replace the diaphragm if required Pressure test the metering unit Connect pressure tester 531 03 06 23 to the fuel hose nipple Lower the carburettor in a vessel with petrol in order to discover any leaks more easily Test the pressure at 50 kPa No leakage is permitted In the event of leakage remove the needle valve In the event of leakage remove the needle valve Loosen the bolt and r...

Page 20: ...ver arm for damage to the groove for the needle valve and wear on the mounting points towards the control diaphragm Replace damaged components with new ones Remove the pump diaphragm Check the diaphragm for damage Remove the fuel screen and clean it or attach a new one Remove the bolt holding the cover over the pump diaphragm Lift off the cover A the gasket B and the diaphragm C Check the diaphrag...

Page 21: ...t Remove the valves and dampers If these components are worn idling is disrupted Always replace the valves and dampers at the same time Assembling the carburettor Blow all channels in the carburettor compartment clean Mount a new plug Use a suitable punch to get a completely tight seal Press in a new main jet Assembling the carburettor Blow the carburettor housing clean Fit a new plug Fit a new ma...

Page 22: ...re turned correctly and that they close completely and tightly in the closed position Use Loctite on the valve screws Attach the various parts of the measuring unit in the reverse order as set out for dismantling The lever arm should lie flush with the carburettor housing Attach the various parts of the measuring unit in the reverse order as set out for dismantling The lever arm should lie flush w...

Page 23: ...emove the 4 screws which hold the heat guard against the cylinder and pull the guard off straight backwards NOTE Do not lose the brass sleeves fitted in the guard Check that the carburettor is sealed No leakage is permitted at 50 kPa Connect pressure tester 531 03 06 23 to the fuel intake on the carburettor Pump up the pressure to 50 kPa Lower the carburettor in a vessel with petrol in order to di...

Page 24: ...he five screws holding together the throttle halves Carefully swing away the right throttle half and note how the different parts are fitted Pay attention when the halves are separa ted so that both rubber elements 1 one on each side are not lost Remove the short circuit cable from the switch 2 Lift up the throttle cable 3 from the chan nel and unhook it from the throttle 4 Lift off the return spr...

Page 25: ...for dismantling Loosen the screw A and pull away the front part of the two piece shaft Separate the throttle halves as described above The front ring shaped vibration damper 7 in the illustration above can now be slid off of the shaft for replacement Assemble the throttle in the reverse order as set out for dismantling Make sure that The throttle return spring is turned the right way The washer un...

Page 26: ...The fuel quantity in relation to the air flow permitted by the throttle opening is adjusted by the L and H jets Turning the needles clockwise gives a leaner fuel mixture less fuel and turning them anticlockwise gives a richer fuel mixture more fuel A lea ner mixture gives higher revs while a richer mixture gives less revs The T screw regulates the position of the throttle while the engine is idlin...

Page 27: ... in terms of rpm the pre programmed fast idle speed 12 500 rpm cannot be exceeded even if the H needle is screwed inwards The risk in this case is still that the engine breaks down as a result of a too lean fuel air mix Limited adjustments of the jet needles can be made with a screwdriver without having to dismantle the stop plugs The needles can be turned max a quarter turn in either direction If...

Page 28: ...4 minutes at 9 500 10 000 rpm 3 Turn the H needle anti clockwise to the limit where the engine starts to splutter 4 Then turn the needle 0 1 turns clockwise 5 Fit the stop plug on the H needle see below Adjustment after cleaning After complete cleaning replacement of carburettor nozzles or complete carburettor both basic setup and fine adjustment must be carried out The basic setup is H 1 2 revs o...

Page 29: ...r damage to the engine A too rich setting of the L and H needles give acceleration problems or a too low working speed NOTE If the cutting equipment rotates while idling the T screw should be turned anticlockwise until it stops NOTE A tachometer should always be used to find the optimal setting Idling speed T screw Let the engine idle for about 30 seconds or until the speed has stabilised Adjust t...

Page 30: ...entrifugal clutch Contents Centrifugal clutch Dismantling ________________ 30 Centrifugal clutch Assembly __________________ 31 Clutch drum and drive axle Dismantling_________ 31 Clutch drum and drive axle Assembly __________ 33 ...

Page 31: ...rcuit cables from their guides Remove the 3 screws E and swing the engine body to one side so the clutch becomes accessible Dismantle the protective plate the cylinder cover and throttle cable on the carburettor Remove the 3 screws E and swing the engine body to one side Dismantle the protective plate under the engine body 3 screws the cylinder cover and the throttle cable on the carburettor Remov...

Page 32: ...attention to the ends of the springs which in addition to wear can also show signs of cracking Assembly Connect the clutch shoes together with the spring NOTE Both clutch shoes should be replaced even if only one of them is showing signs of heavy wear This is to avoid engine vibration caused by imbalance in the clutch Bolt the clutch on the flywheel Do not forget the washers A Note the slots on th...

Page 33: ... of a screwdri ver for possible replacement Dismantle the circlip and press out the clutch drum Dismantle the circlip using circlip pliers Press out the clutch drum using a suitable punch and hammer Dismantle the circlip and heat the clutch cover so the bearing can be dismantled Dismantle the circlip using circlip pliers Heat the clutch case to approx 120 C using a hot air gun Knock the edge of th...

Page 34: ... two piece shaft the guide becomes accessible once the shaft has been split see chapter 3 Dismantle the sleeve A and pull out the guide B by pulling the drive axle Assembly Assemble in the reverse order as set out for dismantling Check that the circlips are fitted correctly in respective slots Lubricate the hole A in the clutch drum s connection on the drive axle using copper paste to aid assembly...

Page 35: ...4 34 Centrifugal clutch ...

Page 36: ...gear Angle gear Contents Gear ratio__________________________________ 36 Dismantling ________________________________ 36 Assembly__________________________________ 37 Drive axle__________________________________ 37 ...

Page 37: ...R 1 1 4 Remove the circlips holding the bearings on the input respective output shafts 3 Remove the circlip D 4 Remove the large circlip holding the ball bearing on the input shaft Dismantling Remove the cutting equipment and guard 1 Remove the screws A and B and lift off the plate C 2 Loosen the screws D and pull the angle gear from the shaft Dismantling Remove the angle gear from the shaft Heat ...

Page 38: ... Heat the gearbox to approx 110 C and first place the output axle in position and then the input axle Make sure the bearing bottoms in its seating Fit the circlips B and C Make sure they lie correctly in their grooves Assemble remaining parts in the reverse order as set out for dismantling NOTE Do not forget the circlip A holding the bearing on the input axle Drive axle Dismantle the sleeve B the ...

Page 39: ...shaft the guide becomes accessible once the shaft has been split see chapter 3 On models with a two piece shaft the guide becomes accessible once the shaft has been split see chapter 3 Dismantle the sleeve A and pull out the guide B by pulling the drive axle ...

Page 40: ...____________________________ 40 Cleaning inspection _________________________ 41 Analysis and actions _________________________ 41 Service tips ________________________________ 46 Wear tolerances ____________________________ 46 Assembly__________________________________ 47 ...

Page 41: ...hly cleaned before being dismantled from the crankcase Dismantling Dismantle the following components to make the cylinder accessible Starter cylinder cover muffler grille muffler with heat guard plate decompression valve and spark plug Dismantle the air filter carburettor and heat guard distance piece see chapter Fuel system Then loosen the 4 bolts holding the cylinder Carefully remove the cylind...

Page 42: ...e discoloured caused by overheating they must be replaced NOTE Scrape carefully with not too sharp a tool so as not to damage the soft aluminium parts Cause Incorrect carburettor setting Recommended max speed exceeded Incorrect oil mixture in the fuel Too low octane fuel Action Insufficient lubrication The piston has small to medium size score marks usually in front of the exhaust port In extreme ...

Page 43: ...xhaust sides Action Cause Wrong type of two stroke oil or petrol Incorrect oil mixture in the petrol Incorrect carburettor setting Piston scoring caused by heavy carbon deposits Too heavy carbon depositing can cause damage similar to that caused by insufficient lubrication However the piston skirt has a darker colour caused by the hot combustion gases that are blown past the piston This type of pi...

Page 44: ...s on the piston s inlet side caused by a broken roller retainer Deep irregular grooves caused by a loose circlip Shown here on the piston s inlet side Piston ring guide pin vibrated loose A too high engine speed can cause the ends of the piston ring to hammer against the guide pin when the piston ring moves in its groove The intensive hammering can drive out the pin through the top of the piston c...

Page 45: ...iston ring groove The piston ring sits firmly in the groove Piston material has been worn away The lower part of the piston skirt is thinner on the inlet side than on the exhaust side Cause Faulty air filter Small dust particles pass through the filter The filter is worn out due to too much cleaning whereby small holes have appeared in the material Unsuitable filter maintenance such as wrong metho...

Page 46: ...red and worn from the piston ring down on the inlet side Extensive damage to the lower part of the piston s inlet side Larger harder particles that enter the engine cause serious damage to the underside of the piston skirt Cause Air filter damaged or missing Parts from the carburettor or intake system have come loose and entered the engine Action Fit the air filter correctly Fit a new air filter F...

Page 47: ... cylinder should be polished as above With deep score marks the piston and cylinder should be replaced Carefully loosen the piston rings and clean the groove well before refitting Carbon deposits in the groove impair the important heat transfer between the piston and cylinder NOTE Be careful with the lower edge of the piston ring groove If this is damaged or if carbon deposits remain the compressi...

Page 48: ...drops of engine oil Assembly Lubricate the gudgeon pin s needle bearing with a few drops of engine oil Direct the arrow on the top of the piston towards the exhaust port Press in the gudgeon pin and fit the circlips NOTE Place a rag in the crankcase opening to prevent the circlip from falling into the crankcase in case it should fly out Check that the circlips are correctly fitted into the grooves...

Page 49: ...6 48 Cylinder and piston ...

Page 50: ... 7 Crankshaft and crankcase Crankshaft and crankcase Contents Dismantling ________________________________ 50 Inspecting the crankshaft______________________ 52 Assembly _________________________________ 52 ...

Page 51: ...or the fuel air mixture when this is sucked from the carburettor and is forced into the cylinder s combustion chamber The crankcase must be perfectly sealed so as not to affect this pump function There cannot be any lea kage from the crankshaft between the crankcase halves or between the crankcase and the cylinder Always replace the sealing rings and gaskets when servicing the crankcase Dismantlin...

Page 52: ...rankcase halves to 110 C using a hot air gun Dismantle the sealing rings from the crankcase halves Dismantle the sealing rings from the crankcase halves Use a suitable punch or sleeve and knock out the sealing rings with the help of a hammer Do this while the crankcase half is still warm if possible Now clean the crankcase halves and crankshaft Knock the crankcase half against a woo den block so t...

Page 53: ...d Inspect the small end of the connecting rod If seizure marks or discolouration are found in the bearing track the crankshaft must be replaced Inspecting the crankshaft The crankshaft cannot be reconditio ned but must be replaced if it is worn or damaged Inspect the large end of the connecting rod If seizure marks discolouration on the sides or damaged needle holders are found the crankshaft must...

Page 54: ...e with a few drops of oil and carefully slide in the crankshaft in the ball bearing so that the sealing ring is not damaged by the shoulder on the stub axle Place the guide rail in position in the flush channel Place the 2 guide sleeves in the crank case half Place a new crankcase gasket on the crankcase and secure if necessary with a little grease Lubricate the tapered crankshaft journal with a f...

Page 55: ...he cylinder base gasket Lubricate the piston and piston rings with a few drops of oil Use the piston ring compressor and care fully slide the cylinder into position Tighten the four screws crosswise Assemble the remaining parts in the re verse order as set out for dismantling See relevant sections in the manual ...

Page 56: ...______________________ 56 Fuel system ______________________________ 56 Centrifugal clutch__________________________ 56 Angle gear _______________________________ 57 Cylinder and piston ________________________ 57 Crankshaft and crankcase___________________ 57 Workshop equipment_______________________ 57 ...

Page 57: ... 03 502 50 18 01 505 69 85 70 502 51 49 01 531 00 48 63 540 06 82 01 531 03 06 23 502 50 18 01 502 51 49 01 502 50 18 01 502 71 14 01 502 50 18 01 503 80 17 01 505 38 13 08 502 50 19 01 502 51 34 02 List of tools Electrical system Centrifugal clutch Starter Fuel system Fuel system ...

Page 58: ...2 50 18 01 505 69 85 70 502 52 42 01 502 50 70 01 502 50 18 01 502 50 70 01 544 13 05 01 544 13 08 01 544 13 09 01 544 13 10 01 544 34 87 01 502 50 19 01 List of tools Angle gear Cylinder and piston Crankshaft and crankcase Workshop equipment Workshop equipment ...

Page 59: ...58 8 List of tools ...

Page 60: ..._____ 60 Ignition system____________________________ 60 Carburettor ______________________________ 60 Clutch __________________________________ 60 Driving __________________________________ 60 Dimensions ______________________________ 60 Vibrations________________________________ 60 ...

Page 61: ... gap mm 0 5 Carburettor Manufacturer Zama C1Q Basic setting H needle turns 1 2 Basic setting L needle turns 1 2 Idle speed rpm 2 800 3 000 Air filter type Foam plastic is oiled Throttle control type Forefinger throttle Clutch 2 shoe clutch Diameter mm 63 Engage speed rpm 3700 Driving Angle gear degrees 35 Angle gear gear ratio 1 4 R 1 29 RJ Control drive disc inch 1 Shaft diameter mm 28 0 Drive ax...

Page 62: ...2008W37 115 11 96 26 ...

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