31 9922cylinder kit
Contents
1. PE 31 9922 CvUNDER KIT MALOSSI HONDA Foresight 4t 250cc PIAGGIO X9 4t 250cc art SI 9922 977 aluminium alloy cylinder Thank you for choosing our modification system We specify that when scooters are fitted with this mod ifi cation they must only be used for competition purposeson a closed circuit To use your modified vehicle on the road you must have it approved once again unless it does not con travene the laws in force in the purchaser s country The new cylinder kits from Malossi for Maxi Scooters are at the cutting edge of applied industry techno logy of cylinder kits for four stroke engines The new cylinderkitsguarantee complete reliability and long life atthe same time ensuring increased tor que and power for your maxi scooter at all engine speeds The new cylinder kits from Malossi have been designed and produced to give you top rate handling under all conditions even the most extreme We also remind you that in orderto obtain top performance all mechanical parts of your vehicle must be in perfect condition and you must scrupulously observe the assembly instructions Technical Data CYLINDER Bore 77 mm Stroke 60 mm Capacity 279 4 Compression ratio 1 11 Maternal Hardened and tempered high silicon content primary aluminium alloy cylinder liner with silicon carbide metal spray coating on a galvanic nickel matrix cross honed with two passes with diamonds for very tight tolerances Machining On high2. hook pull out the camshaft chain Tighten the four box nuts on the stud bolts equally to the torque wrench settings shown in the Assembly Data table Screw in the two M6 side screws that fix the cylinder head to the cylinder block and tighten them to the torque wrench settings shown in the Assembly Data table Remove the inspection plug above the dipstick and bring the crankshaft to top dead centre on the compression stroke Make sure of the exact position by lining up the reference line on the flywheel marked with the letter T with the notch on the crankcase fig 2 and the groove on the camshaft visible through the check hole on the rear cover with the reference line Fit the camshaft chain on the camshaft crown gear lining up the reference line as shown in Fig 3 Fix the camshaft to the cylinder head with its half bearing tightening the two M6 screws to a torque of 10 Nm Manually tension the camshaft chain working on the chain tensioner assembly hole and check that the crown gear is aligned as shown in Fig 3 If necessary move the camshaft chain one tooth forwards or backwardson the crown gear Take care to check often that during engine timing of the camshaft the crankshaft does not move from the position shown by the two aligned reference points in Fig 2 Products reserved exclusively for competitions in places destined for such use in accordance with the provisions of the relative sporting authorit
3. precision numerically controlled machine tools Cylinderand piston selected fora fit of 0 05 mm Heat exchange surfaces recalculated and increased PISTON Supercompact with three rings Maternal Special primary silicon alloy with low thermal expansion and tin metal spray coating on the piston walls Machining on numerically controlled machine tools Lightened and strengthened Heat exchange surfaces increased RINGS Very smooth running special rings with very high mechanical strength S10 chromed nodularcast iron compression rings and chromed alloy steel three piece scraper ring ASSEMBLY INSTRUCTIONS PRELIMINARY OPERATIONS Carefully wash the entire vehicle particularly the engine REMOVING THE ENGINE Disconnect the battery Disconnect all electrical wires that go to the engine and to the starter motor Remove the entire exhaust unit Take off the air filter box Products reserved exclusively for competitions in places destined for such use in accordance with the provisions of the relative sporting authorities Vie decline all responsibility for improper use ISTRUZIONE 73 9922 pag 11 Vey IRADLOSSI 31 9922 cvLINDER KIT s HONDA Foresight 4t 250cc DALOS S PIAGGIO X9 4t 250cc Remove the fuel feed system from the cylinder head leaving it connected to the frame Disconnect the rearbraking system 1 Ifthe rear brake isa shoe brake ora dru
4. G MENTOS fig 1 A lato scarico c t chappement exhaust side AblaRseite lado escape 4 1 P N N o vs ad 2 3 2 3 4 Posizione delle linee di chiusura dei rispettivi segmenti Position de la ligne de fermeture des divers segments Lines of closure of the respective rings Positionen der Schliesslinien der jeweiligen Kolbenringe Posici n de las l neas de cierre de los respectivos segmentos fig 3 Piano testa Plan de la t te Cylinder head surface Ebene Zylinderkopf Plano culata Prodotti riservati esclusivamente alle competizioni nei luoghi ad esse destinate secondo le disposizioni delle competenti autorit sportive Decliniamo ogni responsabilit perl uso improprio ISTRUZIONE 73 9922 pag 24 ERI IRRDLOSSI
5. Remove the rear half bearing of the camshaft loosening the two M6 screws Pull the camshaft chain off the crown gear Remove the two M6 intemal bolts on the chain side that fix the cylinder head to the cylinder block Unscrew with cross procedure the four M8 box nuts on the stud bolts that fasten the cylinder Atthis point draw off the cylinder head and the cylinder Asan extra precaution it isa good rule to close off the crankcase with a clean rag to stop foreign bodies falling into it ASSEMBLY CYLINDER HEAD Even if the scooter has got a low mileage we recommend doing a valve seal test following the instruc tions in the Valve sealing test paragraph With high mileage scooters it is advisable to disassemble the valvesand check that there is not too much play between the rodsand the guides that the valvesare not bent orthe rodsand the valve headswom Even if only one of these components is wom it is advisable to replace both the valves and the guides the same goes for the valve springs If necessary see Useful Advice on page 5 If the valve guides need to be replaced we recommend using a hair dryerto heat up the cylinder head beforehand both for disassembly and assembly After replacing the valve guidestake up the play on the valve seats with a suitable cutter Grind the valves with grinding paste and clean away any encrusted deposits and grinding paste from all parts of the cylinder head Wash and degrease the valves w
6. ble the cylinderhead The grinding must be done with an appropriate tool and with a good quality fine grade grinding paste specifically for grinding valves To increase engine performance we recommend that the inlet and exhaust ports are perfectly blended and polished The best inlet port is one that tendsto taperslightly from the carburettor valve to the inlet valve bya maxi mum of 2 and at the same time does not have any type of iregularities Comers and sudden widening or narowing This is why it must be perfectly blended The best exhaust port is one that tapers out slightly from the exhaust valve by a maximum of 2 and which does not have any type of iregularties and so must be perfectly blended right up to the exhaust silencer Here also there must not be any sudden increases or decreases in the cross section GENERAL C ARE Every time the cylinder kit is disassembled replace the head and bottom gaskets of the cylinder block in orderto guarantee perfect sealing Do not demand maximum engine performance before the optimum working temperature is reached Keep a check on the engine s lubricating system the oil level and the quality of the lubncating oil WARRANTY The components for the modification are guaranteed free from manufacturing faults Parts considered to be faulty can only be returned post free upon our authorisation The waranty does not cover damage deriving from seizure of the cylinder kit or any other damage cause
7. d by this We decli ne all responsibility for improper use of our products Ve hope that you have found the above instructions to be clear enough If something is not clear to you you can contactus by writing or by telephoning during office hours Thank you in advance forthe obser vations and suggestions that you may wish to make to us That s all from Malossi we take the opportunity of congratulating you and we hope you have good fun GOOD LUCK until the next time To obtain the complete listof Malossi products foryour vehicle ask your supplier forthe Malossi Catalogue and any updated illustrative brochures The descriptions given in this public ation are notintended to be binding Malossi reserves the rightto make modifications if considered necessary and not to assume any responsibility for typography and printing errors This publication replaces and annuls all previous publications Products reserved exclusively for competitions in places destined for such use in accordance with the provisions of the relative sporting authorities Vie decline all responsibility for improper use ISTRUZIONE 73 9922 pag 15 SVs IRADLOSSI 31 9922 GRUPPO TERMICO HONDA Foresight 4t 250cc PIAGGIO X9 4t 250cc TOP 1 CROMO N 2 3 gt 4 POSIZIONE CHIUSURA SEG MENTI POSITION DE FERMETURE SEG MENTS RING CLOSURE POSITIONS SC HLIESSPO SITION KOLBENRING E POSICION CIERRE SE
8. ies Vie decline all responsibility for improper use ISTRUZIONE 73 9922 pag 13 ERI RRADLOSSI 31 9922 cvLINDER KIT s HONDA Foresight 4t 250cc DALOS S PIAGGIO X9 4t 250cc Fit the original chain tensioner and tighten its centre nut compressing the spring that adjusts the ten sion of the camshaft chain to a torque of 22 Nm Rotate the crankshaft through 4 or 5 revolutions using an Allen key with a Thandle on the screw that fixes the variator set Take it back to top dead centre aligning the reference lines in Fig 2 and check that the crown gearon the camshaft chain is still aligned as shown in Fig 3 Ifthe crankshaft blocks during rotation do not try to force it Check the engine timing which has evi dently not been done corectly Redo the engine timing following the above procedure with great care Refit the camshaft cover making sure that the crankshaft is still in the position shown with the letter T Fig 2 Check the O ring sealand if damaged replace it Tighten the bolts with cross procedure to a torque of 10 Nm Valve play adjustment Check that the crankshaft has not moved from the position shown in Fig 2 Loosen the two M6 valve play adjustment bolts Inlet valve Tum the adjuster clockwise towards the letter I until the adjuster blocks Tum the adjuster the other way by 1 0 index anticlockwise towards the letter N Exhaust valve Tum the adjuster anticloc
9. ith great care lubricate the rods well and then refit them as they were Cany out the valve seal test following the instructions in the Valve sealing test paragraph Lay a sheet of 1000 grade emery cloth on a perfectly flat surface plate and clean the base of the cylin Products reserved exclusively for competitions in places destined for such use in accordance with the provisions of the relative sporting authorities Vie decline all responsibility for improper use ISTRUZIONE 73 9922 pag 12 EER RADLOSSI re 31 9922 cyviinver KIT ABPTLOSSE HONDA Foresight 4t 250cc PIAGGIO X9 4t 250cc der head that rests on the cylinder block until it is totally white Carefully wash the cylinder head Fitting the cylinder The cylinder block must fit freely onto the crankcase To avoid serious problems proceed as follows Preparations for reassembly Carefully clean away any remains of the onginal gasket from the surface of the crankcase where the cylinder block will rest Fit the crankcase gasket on the crankcase and insert the spigots Before fitting the Malossi cylinder block wash it and degrease it Lower the cylinder without forcing it along the locking stud bolts until it fits onto the crankcase Make sure that there are no components or other small problems in the crankcase that stop the cylinder shell from seating on it If there are any significant points of friction it isadvisable to remove them O
10. kwise towards the letter X until the adjuster blocks Tum the adjuster the other way by 1 0 index clockwise towards the letter E Tighten the two adjuster locking bolts to a torque of 10 Nm Fill the engine with the type of oil recommended by the Manufacturer to the level indicated in the Assembly Data table Check the sparkplug and if necessary reset the electrode gap or replace it with one of the type shown in the Assembly Data table Refit the engine to the vehicle and restore all the connections as they were COOLING CIRCUIT Connect the cooling circuit hoses to the engine and fill the circuit as follows Using the coolant recommended by the Manufacturer fill the expansion tank which is on the central tun nel on the opposite side to the petrol cap to the level marked by Max See the vehicle s maintenance and users manual Fill the radiator through the cap on top of the cylinder kit with the appropriate coolant Disconnect the small tube near the temperature gauge on the cylinderhead and let out all the airin the cooling circuit and then put the tube back in Restore the coolant level in the radiator to Max Start the engine with the scooteron the stand and leave it to run revving it up slightly a few times so that the coolant reachesthe working temperature of 60 70 C Switch the engine off and bleed again discon necting the small tube If necessary restore the level of liquid in the radiator and in the expa
11. m brake you only have to remove the control cable 2 Forhydraulic or mixed braking systems parking brake you have to remove the entire brake pincer leaving it connected to the vehicle s hydraulic system Drain the coolant circuit using the predisposed plugs When the engine iscompletely drained of coolant remove allthe coolant inlet and outlet hoses from the engine itself Remove the rear wheel and the screws or pins that fix the engine to the frame and to the rear shock absorber At this point you have freed the engine from the vehicle We recommend that you place it on a well cleaned workbench orthat you clamp it in a vice ready for the next operations DISASSEMBLING THE CYLINDER KIT Carefully clean the entire engine especially the cylinder block area and the cylinder head using an appropnate detergent and dry everything carefully Drain the engine completely of oil Remove the inspection plug above the dipstick and bring the crankshaft to top dead centre on the compression stroke Make sure of the exact position by lining up the reference line on the flywheel marked with the letter T with the notch on the crankcase fig 2 and the groove on the camshaft visible through the check hole on the rear cover with the reference line Remove the rocker cover Loosen the nut in the centre of the camshaft chain tensioner Remove the chain tensioner assembly unscrewing the two screws that fix it to the original cylinder
12. nce this stage is completed draw off the cylinder and begin the assembly following the instructions below ASSEMBLING THE CYLINDER KIT Carefully clean the piston and blow it off with compressed air Make sure there are no foreign bodies that obstruct the exhaust holes in the oil scraper ring slot Fit one of the two piston clips into the piston making sure that it is perfectly seated in its housing Put the piston on the small end and fix it with the new gudgeon pin taking care to oil it beforehand Fit the other piston clip checking that it is corectly positioned in its housing Putthe oilscraperring spring 5 in the appropriate slot on the piston put in the lowerring 4 and then the top ring 3 that make up the oil scraper ring Fit the second ring with the stamping N pointing towards the top of the piston as shown in Fig 1 Fit the first compression ring with the opening not in line with the opening of the second ring Position the ringsas shown in Fig 1 Fit the chain guide checking that it is perfectly housed in its seat Oil the new Malossi piston and using the appropriate piston ring clamp insert it into the cylinder block while you passa hook through the chain passage in the cylinder block to hold up the chain itself Make sure nothing prevents the cylinder block resting perfectly on the crankcase Fit the new head gasket and the two spigots Insert the cylinder head onto the stud bolts and using the
13. nsion tank MAINTENANCE For running in and maintenance keep scrupulously to the manual Vehicle s maintenance and users manual ASSEMBLY DATA Torque settings M8 box nuts on the stud bolts 24 Nm 2 4 kgm Torque settings M6 side screws on cylinder head 10 Nm 1 kgm Total engine oil capacity 1 3 litres Type see the Vehicle s maintenance and users manual Sparkplug type manufacturer DPR8EA 9 NGK Electrode gap 0 8 0 9 mm Products reserved exclusively for competitions in places destined for such use in accordance with the provisions of the relative sporting authorities Vie decline all responsibility for improper use ISTRUZIONE 73 9922 pag 14 ERI RADLOSSI PE 31 9922 cvLNDER KIT FARLOSSE HONDA Foresight 4t 250cc PIAGGIO X9 4t 250cc VALVE SEALING TEST Inlet and exhaust do the testsone afterthe other Pour petrol in the port until it is full and blow compressed air around the valve head with an air gun to check whether any air bubbles appear inside the port If this happens you have to disassemble the valve and grind it again even if you have already done it If necessary you will have to repeat the operation until the air bubbles stop appearing During the test check that the oil seal on the valve guide does not let any fuel seep through If this happens replace it with a new one USEFUL ADVICE We recommend that you grind the inlet and exhaust valves every time you disassem
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