User manual KTM MXC

250-525 SX, MXC, EXC RACING REPAIR MANUAL ENGINE KTM SPORTMOTORCYCLE AG 5230 Mattighofen Austria www.ktm.at 250-525 SX, MXC, EXC RACING REPAIR MANUAL ENGINE 1 SERVICE-INFORMATIONS 2 GENERAL INFORMATION 3 REMOVING AND REFITTING ENGINE 4 DISASSEMBLING ENGINE 5 SERVICING INDIVIDUAL COMPONENTS 6 ASSEMBLING ENGINE 7 ELECTRICAL 8 FUEL SYSTEM 9 TECHNICAL SPECIFICATIONS 10 PERIODIC MAINTENANCE SCHEDULE 11 WIRING DIAGRAMS 12 13 14 15 16 IMPORTANT INFORMATION/UPDATING INSTRUCTIONS To be able to continue using the existing loose-leaf repair instructions, simply print the following pages and insert them in the existing repair instructions: 14, 21-24, 30-47, 50-52, 56-76, 79-92, 97-124, 134-140, 142, 150-154, 165-167 Remove page (s) 2-1 / 2-7 3-1 4-1 to 4-14 5-1 / 5-3 5-6 to 5-8 5-12 to 5-26 6-1 / 6-4 6-7 to 6-16 7-1 to 7-2 Art.-No. 3206007 -E Replace by page (s) 2-1C 3-1C 4-1C to 4-13C 5-1C / 5-3C 5-6C to 5-8C 5-12C to 5-27C 6-1C / 6-4C 6-7C to 6-17C 7-1C to 7-2C 7-7C to 7-11C 8-1C to 8-21C 9-1C 9-10C to 9-16C 10-1C 11-1C Insert page (s) 2-7C to 2-9C after page 7-7 to 7-11 8-1 to 8-13 9-1 9-10 to 9-13 10-1 11-1 10-8C to 10-11C 11-11C to 11-13C KTM REPAIR MANUAL IN LOOSE-LEAF FORM Repair manual KTM 250-525 SX, MXC, EXC RACING STORING THE REPAIR MANUAL IN THE BINDER ­ Put the index into the binder. ­ Put the front page of the repair manual (210x297 mm) into the transparent pocket provided for this purpose on the outside of the binder. ­ Put the spine label (170x45 mm) into the transparent pocket provided for this purpose on the spine of the binder. ­ Put the summary list of contents (150x297 mm) into the transparent pocket provided for this purpose on the inside of the binder or insert this page on the beginning of the manual. ­ Then insert the individual chapters of the manual between the sheets of the index according to the page number printed in the right bottom corner of each page. Example: page no. 3-5 3 = chapter 3 5 = page 5 All pages with a page number that begins with the digit 3, for example, must be put under the index heading ,,Chapter 3". ­ Index sheets that have not been marked with a certain chapter are for your personal convenience. The respective headings can be entered in the list of contents. EXPLANATION - UPDATING 3.205.85-E Repair Manual 400/520 SX, MXC, EXC RACING Basic version Model year 2000 (Engine number with first digit "0") 2/2000 3.210.01-E Updating of Rep.Manual 3.205.85-E Model year 2001 (Engine number with first digit "1") 1/2001 Art.-No. 3206007 -E 3.210.44-E Updating of Rep.Manual 3.205.85-E Model year 2002 (Engine number with first digit "2") 2/2002 3.206.007-E Updating of Rep.Manual 3.205.85-E Model year 2003 (Engine number with first digit "3") Repair manual KTM 250-525 SX, MXC, EXC RACING 1/2003 Modification / Updating: Technical Details Model 2003 (clutch, valve spring, camshaft gear, carburetor) Technical Specifications, Periodic Maintenance Schedule, Wiring Diagrams Edition 01/2003 INTRODUCTION This repair manual offers extensiv repair-instructions and is an up-to-date version that describes the latest models of the series. However, the right to modifications in the interest of technical improvement is reserved without updating the current issue of this manual. A description of general working modes common in work shops has not been included. Safety rules common in the work shop have also not been listed. We take it for granted that the repairs are made by qualified profesionally trained mechanics. Read through the repair manual before beginning with the repair work. WARNING STRICT COMPLIANCE WITH THESE INSTRUCTIONS ESSENTIAL TO AVOID DANGER TO LIFE AND LIMB. ! CAUTION ! IS NON-COMPLIANCE WITH THESE INSTRUCTIONS CAN LEAD TO DAMAGE OF MOTORCYCLE COMPONENTS OR RENDER MOTORCYCLES UNFIT FOR TRAFFIC ! ,,NOTE" POINTS OUT USEFUL TIPS. Use only ORIGINAL KTM SPARE PARTS when replacing parts. The KTM high performance engine is only able to meet user expectations if the maintenance work is performed regularly and professionally. KTM Austria's certificate of achievement for its quality system ISO 9001 is the beginning of an ongoing total reengineered quality plan for a brighter tomorrow. KTM Sportmotorcycle AG 5230 Mattighofen, Austria All design and assembly modification rights reserved. C by KTM SPORTMOTORCYCLE AG, AUSTRIA All rights reserved REPLY FAX FOR REPAIR MANUALS We have made every effort to make our repair manuals as accurate as possible but it is always possible for a mistake or two to creep in. To keep improving the quality of our repair manuals, we request mechanics and shop foremen to assist us as follows: If you find any errors or inaccuracies in one of our repair manual ­ whether these are technical errors, incorrect or unclear repair procedures, tool problems, missing technical data or torques, inaccurate or incorrect translations or wording, etc. ­ please enter the error(s) in the table below and fax the completed form to us at 0043/7742/6000/5349. ­ NOTE to table: Enter the complete item no. for the repair manual in column 1 (e.g.: 3.210.66-E). You will find the number on the cover page or in the left margin on each right page of the manual. Enter the corresponding page number in the repair manual (e.g.: 5-7c) in column 2. Enter the current text (inaccurate or incomplete) in column 3 by quoting or describing the respective passage of the text. If your text deviates from the text contained in the repair manual, please write your text in German or English if possible. Enter the correct text in column 4. ­ ­ ­ Your corrections will be reviewed and incorporated in the next issue of our repair manual. Item no. of repair manual Page Current text Correct text Additional suggestions, requests or comments on our Repair Manuals (in German or English): Name mechanic/shop foreman Company/work shop 2-1C GENERAL INFORMATION INDEX 2 OIL CIRCUIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ENGINE OIL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CHECKING THE ENGINE OIL LEVEL . . . . . . . . . . . . . . . . . CHANGING THE ENGINE OIL . . . . . . . . . . . . . . . . . . . . . . CHANGING THE OIL FILTERS . . . . . . . . . . . . . . . . . . . . . . CHECKING THE OIL LEVEL OF THE HYDRAULIC CLUTCH BLEEDING OF THE HYDRAULIC CLUTCH . . . . . . . . . . . . . SPECIAL TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CLEANING, STORAGE OF MOTORBIKE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-2 . . .2-3 . . .2-3 . . .2-4 . . .2-5 . . .2-6 . . .2-6 . . .2-7 . . .2-9 Repair manual KTM 250-525 SX, MXC, EXC RACING Art.-No. 3206007 -E 2-2C 3 7 4 6 5 8 11 10 13 1 12 9 2 Art.-No. 3206007 -E Oil circuit Via the long oil screen 2, the oil pump 1 draws engine oil from the oil sump of the transmission. This engine oil flows through an oil line 3 into the cylinder head for camshaft lubrication 4; the oil quantity is controlled by the jet bolt 5. An oil duct branches off to the long oil filter 6 where the coarser particles contained in the engine oil are filtered away. Then, the engine oil arrives at the short oil filter 7 which also filters the fine particles. Now, the purified engine oil is pumped past the bypass valve 8 to the conrod bearing 9 and sprayed from below onto the piston through a nozzle bk. The second oil pump bl draws the engine oil via the short oil screen bm out of the crankcase, thereby lubricating the transmission gears bn. Repair manual KTM 250-525 SX, MXC, EXC RACING 2-3C Engine oil API: SG, SH TEMPERATURE Only use fully synthetic brand oils (Motorex Power Synt. 4T) that meet or surpass the quality requirements of API classes SG or SH (see specifications on the container). ­ 10W 40 10W 50 0°C 32°F + 15W 40 15W 50 ! INSUFFICIENT THE ENGINE. CAUTION ! AMOUNTS OR LOW-GRADE ENGINE OIL LEAD TO PREMATURE WEAR OF Checking the engine oil level The engine oil level can be checked with the engine being either warm or cold. Place the motorcycle in an upright position and on a horizontal surface (not on the side stand). If the engine is cold, the engine oil must be visible at the lower edge of the inspection glass A. B A If the engine is warm, the engine oil must be visible up to the upper edge of the inspection glass B. Replenish the engine oil, if necessary. ! INSUFFICIENT THE ENGINE. CAUTION ! AMOUNTS OR LOW-GRADE ENGINE OIL LEAD TO PREMATURE WEAR OF NOTE: Engines up to the 2001 model have a sight glass and an oil dipstick. If the inspection glass is heavily soiled (e.g. after a race in muddy terrain), the engine oil level can also be measured with the oil dipstick. For this purpose, unscrew the dipstick and wipe it clean with a cloth. Screw the dipstick back in and screw it out again. If the engine is warm, the oil level should be near the MAX mark C. Check engine for leaks. C 2-4C Changing the engine oil NOTE: When changing the engine oil, it is necessary to clean the short and long oil screens and to replace both oil filters. Engine oil has be changed with the engine being at an operating temperature. WARNING AN ENGINE AT OPERATING TEMPERATURE AND THE ENGINE OIL IT CONTAINS ARE VERY HOT - DO NOT BURN OR SCALD YOURSELF! Place the motorcycle on a horizontal surface, remove the plug 1 and allow the oil to drain into a receptacle. Clean plug (with magnet) thoroughly. Once the entire oil has been drained, clean the sealing surface, mount the plug together with the sealing ring and tighten it to 20 Nm/ 15ft.lb. CLEANING THE SHORT OIL SCREEN The short oil screen 2 is accommodated in the hex-socket plug 3 on the engine bottom. Insert a pin-type key into the plug and tap on the key a few times with a hammer in order to relieve the stress acting on the plug. Dismount the oil screen, clean the components thoroughly and blow compressed air through them. Check the O-rings for damage and, if necessary, replace them. Mount the oil screen together with the plug again and tighten the plug to 10 Nm. 1 2 3 Art.-No. 3206007 -E CLEANING THE LONG OIL SCREEN The long oil screen is accommodated in the hexagon plug 4 adjacent the engine number. Dismount the plug together with the oil screen, clean the components thoroughly and blow compressed air through them. Check the O-rings for damage and, if necessary, replace them. 4 Repair manual KTM 250-525 SX, MXC, EXC RACING 5 To mount the long oil screen 5, place it on an approx. 300 mm/ 11.8 in long pin-type key or a similar tool. Insert the pin-type key through the opening into the bore of the opposite engine casing wall. Then, push the oil screen into the engine casing as far as possible. Remove the pin-type key, mount the plug and tighten it to 15 Nm/ 11 ft.lb. ! CAUTION ! THE OIL SCREEN IS MOUNTED SLIGHTLY DOWNWARDS, IF INCORRECTLY FITTED, THE SCREEN LOOSES ITS FUNCTION AND THIS CAN CAUSE INCREASED ENGINE WEAR. 2-5C Changing the oil filters 1 2 2 Remove the bolt 1 and swing the brake fluid container sideward. Place a receptacle underneath the engine to collect the drained oil. Remove the 4 bolts 2 and dismount the two oil filter covers. 2 2 3 Using circlip pliers, you may now pull the oil-filter inserts 3 out of the housing. Clean the oil filter cover, the sealing surfaces of the O-rings and the engine casing. Check the O-rings of the oil filter covers for damage and, if necessary, replace them. 3 4 Put the motorcycle on its side and fill the oil filter housings about halfway with engine oil. Insert the long oil filter at the front and the short oil filter at the back of the housing. Grease the O-rings 4 of the oil filter covers and mount the cover. Mount the bolts and tighten them to 6 Nm/5 ft.lb. Position the brake fluid container and tighten the bolt to 8 Nm/ 6 ft.lb. Return the motorcycle to an upright position. Remove the oil dipstick 5 at the clutch cover and fill in 1.2 liters of fully synthetic engine oil (Motorex Power Synt. 4T). 5 Start the engine and check all screwed connections and oil filter covers for leaks. Finally, check the engine oil level and, if necessary, correct it. 2-6C 1 Checking the oil level of the hydraulic clutch To check the oil level in the master cylinder of the clutch remove the cover. For this purpose, remove bolts 1 and cover together with the rubber boot 2. The oil level in the horizontal-standing master cylinder should be 4 mm (0,157 in) below the upper edge. If necessary add SAE 10 biodegradable hydraulic oil. ! CAUTION ! ONLY USE SAE 10 BIODEGRADABLE HYDRAULIC OIL TO REFILL THE MASTER CYLINDER. NEVER USE BRAKE FLUID! 2 Bleeding of the hydraulic clutch For bleeding, the cover of the master cylinder of the clutch needs to be removed. For this purpose, remove screws 1 and take off cover together with rubber bellows 2. At the slave cylinder of the clutch, remove the bleeder nipple. At its place, mount the bleeder syringe 3 which is filled with biodegradable hydraulic oil. 3 Refill oil, until oil is discharged from the bore A of the master cylinder in a bubble-free state. Make sure that the oil does not overflow. ! Art.-No. 3206007 -E CAUTION ! A COMPLETED THE BLEEDING PROCEDURE, YOU HAVE TO VERIFY THAT THE OIL LEVEL IN THE MASTER CYLINDER IS CORRECT. FOR FILLING OF THE MASTER CYLINDER, USE SAE 10 BIODEGRADABLE HYDRAULIC OIL ONLY. NEVER USE BRAKE FLUID NOR MIX BIODEGRADABLE HYDRAULIC OILS WITH MINERAL OILS. HAVING Repair manual KTM 250-525 SX, MXC, EXC RACING 2-7C 4 19 18 2 1 10 8 21 9 7 13 12 20 11 16 6 17 15 3 14 24 5 22 23 2-8C SPECIAL TOOLS ­ ENGINE FIG 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Repair manual KTM 250-525 SX, MXC, EXC RACING PART NO. 560.12.001.000 590.29.002.000 590.29.020.000 590.29.005.010 510.12.011.000 590.29.021.000 598.29.015.075 580.12.015.089 580.12.015.095 6 899 785 584.29.059.000 151.12.017.000 151.12.018.000 151.12.018.100 590.29.026.006 590.29.035.000 590.29.036.000 590.29.033.000 590.29.019.000 584.29.037.037 590.29.034.000 580.12.009.000 309098 510.12.012.000 590.29.072.000 503.29.050.000 590.29.041.000 590.29.003.100 DESCRIPTION Universal engine work stand Engine holder for engine work stand Rivetting tool for steering chain Mounting sleeve for shaft seal ring water pump Circlip pliers Puller for driving hub and primary gear Piston ring spanner Ø 75 mm Piston ring spanner Ø 89 mm Piston ring spanner Ø 95 mm Loctite 243 blue 6 cm3 Loctite 648 green 20 ml Gear puller Internal gear puller 12-16 mm Internal gear puller 18-23 mm Limit plug gauge 6.05 mm Mounting sleeve for driving pin Protection sleeve for primary gear Puller for camshaft bearings Valve spring mounter Mounting tool for inner rings of crankshaft bearings Wrench for mixture regulating screw Magneto extractor Seal (Three-Bond) Chain sprocket holder Spark plug wrench 16 mm Bleeding syringe for hydraulic clutch Feeler gauge for valve clearance Clutch holder Art.-No. 3206007 -E 2-9C CLEANING Clean your motorcycle regularly in order to maintain the beauty of its plastic surfaces. The best manner would be to use warm water that has been mixed with a normal brand-name washing detergent and a sponge. The hard dirt can be removed before washing with the help of a soft water jet. ! NEVER CAUTION ! CLEAN YOUR MOTORCYCLE WITH A HIGH-PRESSURED CLEANER OR A HIGH-PRESSURED WATER JET. THE WATER COULD OTHERWISE RUN INTO THE ELECTRICAL COMPONENTS, CONNECTORS, SHEATHED CABLES, BEARINGS, CARBURETOR, ETC. AND CAUSE DISTURBANCES OR LEAD TO A PREMATURE DESTRUCTION OF THESE PARTS. ­ You should use normal brand-name detergents to clean the motorcycle. Especially dirty parts should be cleaned additionally with the help of a paint brush. ­ Before cleaning with water, plug the exhaust pipe to prevent water ingress. ­ After the motorcycle has been rinsed with a soft water jet, it should be dried by air pressure and a cloth. Drain the float chamber of the carburetor. Then take a short drive until the engine has reached the working temperature and also apply the brakes. By warming these components, the residual water can evaporate from inaccessable parts of the engine and the brakes. ­ Slide back the protective covers on the handlebar-mounted instruments so that any water that may have seeped into this part of the motorcycle is allowed to evaporate. ­ Once the motorcycle has cooled down, oil or grease all sliding and bearing points. Treat the chain with a chain spray. Also oil the fuel tap. ­ To avoid malfunctioning of the electric system, you should treat the emergency-OFF switch, short-circuit button, light switch and socket connectors with a contact spray. CONSERVATION FOR WINTER OPERATION In the event that the motorcycle is also used in winter and on roads where one has to expect salt spraying, you will have to take precautions against the aggressive road salt. ­ clean motorcycle thoroughly and let it dry after each ride. ­ treat engine, carburetor, swing arm, and all other bare or galvanized parts (except for brake discs) with a wax-based anti-corrosion agent. WARNING KEEP ANTI-CORROSION AGENT FROM GETTING INTO CONTACT WITH THE BRAKE DISCS, FOR OTHERWISE THIS WILL SIGNIFICANTLY REDUCE THE BRAKING POWER. ! AFTER CAUTION ! RIDES ON SALTED ROADS, CLEAN MOTORCYCLE THOROUGHLY WITH COLD WATER AND LET IT DRY WELL! STORAGE Should you desire to make a pause over a longer space of time, please observe the following instructions: ­ Clean motorcycle thoroughly. ­ Change engine oil, short and long oil filters (old engine oil contains aggressive contaminants). ­ Check antifreeze and amount of cooling liquid. ­ Warm up the engine once again, close the fuel cock and wait until the engine dies. Then open the drain plug from the float chamber to remove the remaining fuel. ­ Remove spark plug and fill in approx. 5 cc of engine oil into the cylinder through the opening. Actuate kick-starter 10 times in order to distribute the oil onto the cylinder walls and mount the spark plug. ­ Set piston to compression so that the valves will be closed (slowly operate the kickstarter until you can hear the automatic decompressor click (release). ­ Let fuel flow out of tank into an appropriate container. ­ Correct tire pressure. ­ Lubricate pivot points of the control levers, footrests, etc. as well as the chain. ­ Service the shock absorber linkage. ­ Disassemble and charge battery. ­ The storage place should be dry and not subject to excessive temperature fluctuations. ­ Cover the motorcycle with an air permeated tarpaulin or blanket. Do not use non air permeable materials as any humidity may not be able to escape and could cause corrosion. ! DO CAUTION ! NOT LET THE ENGINE RUN FOR A SHORT TIME DURING THE STORAGE PERIOD. THE ENGINE WOULD NOT GET WARMED UP ENOUGH AND THE THUS DEVELOPED STEAM WOULD CONDENSE DURING THE COMBUSTION PROCESS AND CAUSE THE VALVES AND EXHAUST TO RUST. RE-INITIATION AFTER TIME OF STORAGE ­ ­ ­ ­ Mount the charged battery (match polarity). Fill up tank with fresh fuel. Check motorcycle as before each start (see driving instructions). Take a short, careful test ride first. 3-1C DISMOUNTING AND MOUNTING THE ENGINE INDEX 3 DISMOUNTING THE ENGINE . . . . . . . . . . . . . . . . . . . . . . . . . . MOUNTING THE ENGINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BLEEDING THE COOLING SYSTEM . . . . . . . . . . . . . . . . . . . . . . CHECKING THE ADJUSTMENT OF THE HAND DECOMPRESSION RELEASE CABLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADJUSTING THE THROTTLE CABLES . . . . . . . . . . . . . . . . . . . . . . . .3-2 . . . .3-5 . . . .3-5 . . . .3-5 . . . .3-5 Repair manual KTM 250-525 SX, MXC, EXC RACING Art.-No. 3206007 -E 3-2C Dismounting the engine 1 ­ Clean the motorcycle thoroughly and prop it up on a stable stand. ­ Dismount the seat and the tank with spoilers. ­ Disconnect the ground cable 1 of the battery. ­ Remove the screw 2 and detach the 2 tension springs 3. 2 3 ­ Detach the 2 tension springs 4, pull exhaust pipes forward and take them off the vehicle. 4 Art.-No. 3206007 -E ­ Detach the 2 tension springs 6 and remove the screw 5. ­ Pull the intermediate pipe forward and take it off the vehicle. 6 Repair manual KTM 250-525 SX, MXC, EXC RACING 5 ­ Disconnect all plug-and-socket connections of the ignition system. ­ Unhitch the cable of the hand decompressor at the engine. ­ Pull out the spark plug connector. 3-3C ­ Remove the carburetor cover and unhitch both throttle cables. ­ Detach the return spring 1 of the footbrake pedal. ­ Remove the 2 screws 2 and take off the frame cover. 2 1 5 ­ Open the radiator cap. ­ Remove the screw 3 at the cylinder together with the sealing ring and drain the coolant into a receptacle. ­ Disconnect the water hoses 4 and 5. ­ Disconnect the hose of the engine ventilation system 6. 6 3 4 ­ Disconnect the plug-in connection from the throttle-valve sensor. ­ Loosen the front and rear hose clamps of the carburetor, pull the carburetor backward and pivot it out of the rubber sleeve at the front. ­ Take the carburetor off the vehicle. 7 8 ­ Disconnect the cable 7 from the E-starter motor. ­ Disconnect the plug-and-socket connection 8. ­ Remove the screw 9 and swing the brake-fluid container sideward. 9 3-4C ­ Remove the bolts 1 and take off the sprocket cover. ­ Remove the 2 bolts 2 of the clutch slave cylinder and pull the clutch slave cylinder off the casing. 1 1 ­ Swing the chain damper plate backwards. ­ Open the chain joint and remove the chain from the vehicle. 2 ­ Remove the bolt 3 and take off the cable clip. NOTE: From Model 2001 onwards a cable tie is mounted instead of the the cable clip. 3 ­ Disconnect the radiator hose 4 and dismount the tank roller 5. 5 Art.-No. 3206007 -E 4 ­ Dismount the front engine mounting bolt 6. Repair manual KTM 250-525 SX, MXC, EXC RACING 6 ­ Remove the engine mounting bolt 7 and the hex nut 8. ­ Dismount the swing arm pivot and pull the swing arm backwards. ­ Lift the engine out of the frame. 8 7 3-5C Mounting the engine ­ The engine is mounted exactly the reverse order. Be sure to use the correct fastening torques (see technical specifications). ­ After a short, careful test ride, check engine oil and coolant level once more. Bleeding the cooling system 1 To bleed the cooling system, fill in approx. 0.8 liters (0.2 US gallons) of coolant and remove the bleeder bolt 1. Do not reinstall the bleeder bolt until coolant escapes at the bore without any bubbles. Then, fill in the coolant until it reaches a level about 10 mm above the radiator fins. After a short ride, check the coolant level once more. Checking the adjustment of the hand decompression release cable 3 10 mm 4 2 Start the engine and, at idling speed, slowly pull the hand decompression lever until you can feel the thumping of the rocker arm on the lever. The backlash until said thumping should be approx. 10 mm, measured at the lever's outer end. If necessary, correct this backlash. To adjust move back the protective cover 2, loosen the counter nut 3 and correct the adjustment screw 4 accordingly. Tighten counter nut and push back protective cover. ! IF CAUTION ! THERE IS NO PLAY IN THE DECO-LEVER, THIS CAN RESULT IN ENGINE DAMAGE. Adjusting the throttle cables 6 7 5 The throttle grip should always provide for a backlash of 3-5 mm. Besides, with the engine running, the idling speed must not change if you turn the handlebar all the way to the left or right. To adjust the throttle cables, dismount the seat and the tank together with spoilers. Slide back the protection cover 5. Loosen the counter nut 6 and turn the adjusting screw 7 accordingly. Turning the adjusting screw counterclockwise will reduce the backlash, turning the adjusting screw clockwise will increase the backlash. Tighten the counter nut and check whether the throttle grip can be actuated smoothly. Mount tank and seat. 4-1C DISMANTLING THE ENGINE INDEX 4 DRAINING THE ENGINE OIL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-2 DISMOUNTING THE OIL FILTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-2 DISMOUNTING THE CHAIN WHEEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-2 DISASSEMBLING THE CLUTCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-3 DISMOUNTING THE IGNITION SYSTEM (400/520 MODELS UNTIL 2002) . .4-3 DISMOUNTING THE IGNITION SYSTEM AND LOOSENING THE PRIMARY GEAR (250 EXC MODELS FROM 2002, 450/525 MODELS FROM 2003) . .4-4 REMOVING THE FLYWHEEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-5 REMOVING THE CLUTCH DRIVE AND THE OUTER CLUCH HUB . . . . . . .4-5 DISMOUNTING THE OIL PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-6 DISMOUNTING THE UPPER CYLINDER HEAD PORTION . . . . . . . . . . . . . .4-7 DISMOUNTING CYLINDER HEAD, CYLINDER AND PISTON . . . . . . . . . . .4-7 DISMOUNTING THE TIMING CHAIN AND THE TIMING GEAR . . . . . . . . .4-9 DISMOUNTING THE E-STARTER DRIVE GEAR AND KICKSTARTER . . . . . .4-10 DISMOUNTING THE PRIMARY GEAR AND FREEWHEEL . . . . . . . . . . . . .4-11 DISMOUNTING THE SHIFT MECHANISM AND TRANSMISSION . . . . . . .4-12 DISMOUNTING THE BALANCER SHAFT AND CRANKSHAFT . . . . . . . . . .4-13 Repair manual KTM 250-525 SX, MXC, EXC RACING Art.-No. 3206007 -E 4-2C 2 3 Draining the engine oil ­ Remove the bolts 1, 2, and 3, and drain the engine oil into a receptacle. ­ Remove kickstart and shift lever. 1 Dismounting the oil filter 4 ­ Unfasten the 4 bolts and remove both oil filter covers 4. 4 ­ Pull the 2 oil filters out of the housing. NOTE: To pull out the oil filters, you should use circlip pliers (see photo). Art.-No. 3206007 -E Dismounting the chain wheel Repair manual KTM 250-525 SX, MXC, EXC RACING 5 7 6 ­ Remove collar bolt 5 and disc spring. ­ Take the chain wheel off the countershaft. ­ Pull the spacer bushing off the countershaft. NOTE: If the transmission and clutch of the engine are okay, you can engage a gear in order to block the countershaft (force transmission to the blocked crankshaft does exist). If the countershaft cannot be blocked as described above, you have to use a holding spanner to steady the chain-wheel in order to unfasten the collar bolt. ­ Pull push rod 6 out of the main shaft. ­ Loosen the 2 bolts 7 and dismount the E-starter motor. 4-3C Disassembling the clutch ­ Loosen all bolts of the clutch cover and dismount clutch cover together with gasket. ­ Pull the 2 dowels out of the engine casing. ­ Loosen the bolts in a crosswise order to prevent the clutch discs from getting jammed when the clutch springs are released. ­ Dismount the pressure cap together with bolts, spring retainer, and clutch springs. ­ Remove the pressure piece 1. ­ Take all lining and steel discs out of the outer clutch hub. ­ Remove all 12 driving pin sleeves 2 (from model 2002 on). 1 4 2 3 6 Up to the 2002 model: ­ Remove the circlip 3. From 2003 model: ­ Bend up the lock washer 4 with a flat chisel, position the clutch holder 5 with 6 driving sleeves as shown and loosen the nut 6. NOTE: Do not remove the clutch holder to allow the flywheel nut to be removed later. 5 Dismounting the ignition system (models 400/520 until 2002 only) ­ Unfasten the 4 bolts 7 and take the ignition cover together with the seal off the engine casing. 7 7 4-4C ­ Turn crankshaft to TDC. A NOTE: In the TDC position, the guidepiece A will be above the pulser coil (see photo). 1 ­ Turn out the crankshaft fixing bolts 1 and remove the sealing ring 2. ­ Turn in the crankshaft fixing bolt by hand. ­ If you feel any resistance, move the flywheel slightly back and forth so that the crankshaft fixing bolt may engage the recess of the crankshaft. ­ Tighten the crankshaft fixing bolt to 10 Nm/8 ft.lb. 2 ­ Loosen the collar nut 3 and remove the spring washer. 3 Art.-No. 3206007 -E NOTE: When ordering a new part, a forged rotor will be supplied, this part is produced without rivets and is interchangeable. Dismounting the ignition system and loosening the primary gear (model 250 EXC from 2002, models 450/525 from 2003) Repair manual KTM 250-525 SX, MXC, EXC RACING 4 ­ Unfasten the 4 bolts 4 and take the ignition cover together with the seal off the engine casing. 4 5 ­ Holding the clutch holder mounted earlier, unscrew the nut 5. ­ Remove the clutch holder. ! SINCE CAUTION ! A LONGER CRANKSHAFT LOCATING SCREW IS MOUNTED ON THE 250 EXC MODELS, IT IS IMPERATIVE THAT YOU HOLD THE CLUTCH HOLDER WHILE UNSCREWING THE NUT 5, OTHERWISE YOU MAY BEND THE LOCATING SCREW AND DAMAGE THE ENGINE HOUSING. 4-5C ­ Apply the special tool as shown, loosen the collar nut from the primary gear and remove. ­ Remove the special tool. ! CAUTION ! COLLAR NUTS WITH LEFT-HAND THREAD AND WITH RIGHT-HAND THREAD WERE USED RESPECTIVELY. COLLAR NUTS LABELED AS "LEFT" HAVE A LEFT-HAND THREAD. COLLAR NUTS WITHOUT LABELING HAVE A RIGHT-HAND THREAD. ­ ­ ­ ­ 1 Turn the crankshaft to the TDC position (see illustration on page 4-4C). Turn out the crankshaft fixing bolts 1 and remove the sealing ring 2. Turn in the crankshaft fixing bolt by hand. If you feel any resistance, move the flywheel slightly back and forth so that the crankshaft fixing bolt may engage the recess of the crankshaft. ­ Tighten the crankshaft fixing bolt to 10 Nm/8 ft.lb. 2 Pulling off the flywheel ­ Loosen the 2 bolts 3 and take the pulse generator out of the engine casing. ­ Mount the puller tool and pull off the flywheel. For the pull-off step, use the protection cover. ­ Remove the Woodruff key from the crankshaft. 3 ­ NEVER ­ ! CAUTION ! USE A HAMMER OR OTHER TOOLS TO HIT AGAINST THE FLYWHEEL. THIS MIGHT CAUSE THE MAGNETS TO COME OFF THE FLYWHEEL AND THE CRANKSHAFT TO BE DAMAGED. HOLD THE PULLER TOOL TO PREVENT THE LOCATING SCREW FROM BEING BENT (250 EXC MODEL). Removing the clutch drive and the outer clutch hub 4 5 ­ Insert the protection cover into the main shaft and mount the puller tool. ­ Pull the inner clutch hub off the main shaft. ­ Take the outer clutch hub 4 together with the bearing bush and the 2 stop discs off the main shaft. NOTE: In the 2001/2002 models, disk 5 is replaced by a stepped disk and the bushing by 2 needle bearings 6 (see illustration). 5 4 6 4-6C 3 From the 2003 model: ­ Remove the outer clutch hub 1 together with the stepped disk 2 and both half disks 3 from the main shaft. 2 ­ Remove both needle bearings 4 and the supporting plate. 2 1 3 4 Dismounting the oil pump ­ Loosen the 2 bolts 5 and remove the oil pump cover. Art.-No. 3206007 -E 5 ­ Pull needle roller 6, inner rotor 7 and outer rotor 8 out of the oil pump casing. Repair manual KTM 250-525 SX, MXC, EXC RACING 8 7 6 ­ Remove banjo bolt 9 and jet bolt bk together with their sealing rings and dismount the oil line. 10 9 4-7C Dismounting the upper cylinder-head portion ­ Loosen each of the 6 bolts together with their sealing rings and dismount both valve covers 1 together with their gaskets. ­ Unscrew the spark plug. 1 ­ Unfasten 4 bolts and dismount the water pump cover 2 together with its gasket. 2 ­ Loosen all bolts 3 of the upper cylinder head part. 3 3 3 3 3 ­ Use a plastic hammer to carefully tap upwards in area A and lift off the upper cylinder head part. A Dismounting cylinder head, cylinder and piston 4 ­ Dismount the bolt 4 together with the sealing ring and the pressure spring. ­ Unfasten the 2 bolts and pull the timing-chain tensioner out of the cylinder. 4-8C ­ Apply the timing chain separating tool and open the timing chain by turning the spindle (see photo). ! CAUTION ! ­ MAKE SURE THAT THE PUSHED-OUT BOLTS DO NOT FALL INTO THE ENGINE. ­ PREVENT THE TIMING CHAIN FROM FALLING INTO THE CHAIN TUNNEL. ­ THE OPENED RIVET LINK IS TO BE DISCARDED. NOTE: Every rivet link of the timing chain can be opened. ­ To keep the timing chain from falling into the chain tunnel, you should insert a cable tie through the ends of the timing chain. ­ Extract the camshaft from the cylinder head. ­ Remove the 3 bolts 1. NOTE: ­ If no repairs to the cylinder and cylinder head are necessary, these 3 bolts need not be removed. You can dismount the cylinder and the cylinder head as one. In this case, the cylinder head gasket need not be replaced. ­ from Model 2001 onwards the bolt outside the chain tunnel is mounted with a copper seal ring (6x10x1) Art.-No. 3206007 -E 1 1 ­ Remove the 4 cylinder-head bolts 2 together with washers and dismount the cylinder head together with the cylinder head gasket. Repair manual KTM 250-525 SX, MXC, EXC RACING 2 ­ Pull the cylinder upward while holding the piston. 4-9C ­ Remove the wire circlip and the push piston bolt from the piston. Dismount the piston. Dismounting timing chain and timing gear ­ Loosen the 2 bolts 1 and dismount the fall-out protection element 2. ­ Remove the timing chain. 1 1 2 ­ Remove the bolts 3 and 4. Pull timing chain tensioner and timing chain guide upward out of the engine casing. 4 3 ­ Remove circlip 5. 5 ­ Apply the puller tool and pull the timing gear off the crankshaft. 4-10C 2 1 3 Dismounting E-starter drive gear and kickstarter ­ Remove the 2 circlips 1 and the stop discs. Pull the kickstarter idler gear 2 and the E-starter idler gear 3 off the bearing bolts. 1 ­ Pull the reduction gear and the needle bearing off the bearing bolt. Take the bearing bolt out of the engine casing. ­ Carefully loosen the collar bolt 4 while holding down the kickstarter spring. Release the kickstarter spring and unhitch the spring shackle. ! Art.-No. 3206007 -E CAUTION ! 4 CAREFUL WHEN RELEASING THE KICKSTARTER SPRING, AS THE RECOILING KICKSTARTER SPRING MAY CAUSE INJURY. BE ­ Pull the kickstarter shaft together with ratchet gear, spring, and disc out of the engine casing. Repair manual KTM 250-525 SX, MXC, EXC RACING 6 5 8 ­ Slide back the sliding plate and pull the shift shaft together with the stop disc 5 out of the engine casing. ­ Remove the bolt 6 and dismount the shift arrester. ­ Remove the bolt 7, dismount the arrester lever together with bushing and spring. NOTE: The arrester lever only needs to be dismounted if the engine casing is exchanged. ­ Remove the tab washer 8. Pull stop disc, oil pump wheel, and needle roller off the oil pump shaft. 7 4-11C Dismounting primary gear and free wheel ­ Remove the collar nut 1. 1 2 ! CAUTION ! COLLAR NUTS WITH LEFT-HAND THREAD AND WITH RIGHT-HAND THREAD WERE USED RESPECTIVELY. COLLAR NUTS LABELED AS "LEFT" HAVE A LEFT-HAND THREAD. COLLAR NUTS WITHOUT LABELING HAVE A RIGHT-HAND THREAD. NOTE: The collar nut 1 was already removed from the 250 EXC models from 2002 and the 450/525 models from 2003 as described on page 4-5. ­ Loosen the 2 bolts 2 and dismount the oil pump cover. 4 3 ­ Take the oil pump shaft together with needle roller, inner rotor 3 and outer rotor 4 out of the engine casing. ­ Remove 2 bolts 5 opposite located. 5 ­ Mount the puller tool and pull the primary gear off the crankshaft. ­ Loosen the crankshaft fixing bolt. ­ Loosen each of the 13 casing bolts. 4-12C Dismounting shift mechanism and transmission ­ Turn the engine sideward. ­ Unfasten the engine fixture at the engine work stand ­ Applying a suitable tool to the cast-on members on the casing, lift off the left half of the casing, or separate it from the right half by slightly tapping on the countershaft with a plastic hammer. ! CAUTION ! TRY TO AVOID PRYING THE HALVES APART WITH A SCREWDRIVER OR A SIMILAR TOOL AS THIS IS APT TO INFLICT DAMAGE ON THE SEALING SURFACES. ­ Dismount the left casing half and the gasket. ­ Pull the 2 dowels out of the engine casing and secure the right half of the casing in the work stand. ­ Remove the stop disc 1, O-ring 2, and inner ring 3. ­ Pull both shift rails 4 together with the 4 springs out of the engine casing and swing the shift forks sideward. 3 1 2 4 4 6 Art.-No. 3206007 -E ­ Pull the shift roller 5 out of the bearing seat. ­ Remove the shift forks 6. 5 NOTE: During disassembly, watch out for the shift rolls A on the driving pins of the shift forks. They may remain in the shift roller. A 6 ­ Pull main shaft and countershaft out of the bearing seats simultaneously. Repair manual KTM 250-525 SX, MXC, EXC RACING ­ Take 1st speed idler gear 7 together with needle cage and the two stop discs out of the engine casing. 7 4-13C Dismounting balancer shaft and crankshaft ­ Turn the crankshaft until the marks on the balancer shaft and crankshaft match. ­ In this position, the balancer shaft can be pulled out of the bearing seat. ­ Pull the crankshaft out of the bearing seat. ­ Clean all components, check them for wear and, if necessary, replace them with new ones. NOTE: For a complete engine overhaul procedure, we recommend that you replace all gaskets, shaft seal rings, O-rings, and bearings. 5-1C SERVICING INDIVIDUAL COMPONENTS INDEX 5